Set among the boats and barges of a riverside pierhouse in London, Lloyds, Barclays, NatWest, British Business Bank, Tide, Santander and Unity Trust Bank came together over lunch to share ideas, challenges and opportunities. 

❮ ❯

Three themes stood out from the conversation:

1. “Perseus is like open banking for sustainability.”

Open Banking has already delivered an estimated £8.3bn for the UK economy, with the potential opportunity, once it reaches full maturity, estimated at £43bn per year.

Its success has come from giving consumers greater control over their financial data, enabling better financial management, creating productivity gains for businesses and improving access to finance.

The model at the heart of Open Banking is simple: your financial data stays with your bank, while authorised third parties can access it securely through standardised infrastructure. 

Perseus follows the same principles. 

Sustainability data can remain with the organisation that holds it,  whether that’s a utility, data provider, carbon accounting platform or smart meter provider, while authorised organisations can securely access it when they need to.

You don’t need to move all your data to one platform, and you don’t need to build the infrastructure yourself. Perseus provides the shared infrastructure that enables data to flow between organisations, unlocking new products and services and helping to realise its own £5–10bn opportunity in sustainable finance.

The parallels with Open Banking don’t end there. Perseus and Open Banking share many of the same users and stakeholders, and the project is exploring integration with Open Banking to enable greater cross-sector interoperability.

2. “If you're happy for us to access the data, you can use any Carbon Accounting Provider you choose.”

Open Banking doesn’t require everyone to use the same bank. You can bank with whoever you chose and still access third-party financial services.

Perseus works in the same way. It isn’t about choosing one platform or picking a ‘winner’. It’s about interoperability: allowing customers to use different providers while enabling data to flow securely between them.

Perseus demonstrates the value of an interoperable approach to smart data sharing, connecting energy data providers, carbon accounting platforms and financial service providers through common governance.

3. “Collaboration across the sector is the only viable path.”

Collaboration is the business model.

Icebreaker One’s governance structure is designed to enable that collaboration. It gives members the opportunity to shape how Perseus is built and who it benefits. 

By bringing members together through Advisory Groups, Steering Groups and an independent Delivery Oversight Committee, Perseus creates a collaborative, and precompetitive environment, all crucial elements to help develop the UK’s first cross-sector Smart Data Scheme. 

The alternative is individual organisations building proprietary approaches and contributing to the creation of a fragmented ecosystem. Instead, Perseus provides shared infrastructure that gives FSPs the opportunity to experiment, innovate and develop new services, while reducing duplicated effort.

Get involved now: if you want to be one of the members shaping the future of Perseus and sustainable finance, join now. 

Meeting Aims 

1. Update on the roadmap, AGs and DOC
2. Discuss engagement and tactics for Perseus
3. Plan a 2026 gathering

Summary:

• It was agreed that:
  • Five live case studies remain the year-end delivery target.
  • The Perseus for Domestic briefing note will be circulated
  • Innovation workshops with individual members will be explored as a complement to the top-down engagement approach.
  • AG4 will build a joined-up coalition narrative, including what it means for end customers
• It was noted that:
  • Xero has joined as a new member alongside Intuit and Sage, giving the ecosystem combined reach to over 1 million SMEs.
  • 2026 roadmap milestones are broadly on track, albeit with FSP case studies slow, but progress is being made. Q3 priorities include agreeing interoperability with Open Banking.
  • Palace of Westminster events are planned for the autumn with a sponsor secured: a build-up session in a committee room and a larger terrace event.
  • AG1 highlighted the need to resolve marketing permissions, embed finance where the customer is, and consider energy intensity as a metric.
  • AG2 highlighted sandbox improvements, better synthetic data, member-contributed datasets, and a planned autumn developer meetup focused on AI-assisted integration.
  • AG4 highlighted the need to demonstrate short-term value to members, tailor communications to different organisational priorities, and better articulate non-product value.
  • The DOC highlighted that Perseus’ financial outlook for 2026 has been revised down again, as membership commitments in principle are converting slowly to paid invoices. Prioritisation is ensuring core delivery is on track and the Perseus team is focusing on helping members deliver use cases.
• It was discussed that:
  • Identifying advanced, specific SME users who could champion Perseus use cases, would complement top-down institutional messaging with bottom-up engagement.
  • Messaging should lead with opportunity and optimism. There is scope to interlock with the Climate Hub’s existing “grow, save costs, be resilient” framing.
  • Members imagining the counter-outcome: without Perseus reaching scale, sustainable finance risks will fail to reach mass market.
  • ‘Perseus for Domestic’ could align with the Warm Homes Initiative, this is at a coalition-building and political alignment stage.

Next meeting: Monday 2 November 2026 13:00-15:00 BST

Formal records, including attendees, are maintained by the secretariat. 

These are confidential to the Steering Group Members.

With over 5 million customers worldwide, Xero is a leader in cloud accounting across New Zealand, Australia and the UK, bringing valuable expertise in supporting SMEs through connected digital tools and services.

As part of Perseus, Xero will contribute to a coalition of like-minded industry leaders exploring how trusted, interoperable data-sharing can simplify sustainability reporting for SMEs. With Perseus targeting a £5–10bn opportunity in embedded sustainable finance, the collaboration reflects the wider evolution of Smart Data and Open Finance in the UK and beyond, creating more connected, efficient ways for organisations and individuals to share and use data securely.

“Project Perseus is a practical example of how Smart Data can solve real problems for small businesses. Xero sees value in work that helps create trusted, interoperable approaches to emissions and sustainability data, making reporting simpler and helping build stronger foundations for better access to finance and future Open Finance innovation.”

Stuart Miller
Director, Public Policy & Technology Research, Xero

Meeting Aims:

1. Identify how comms and engagement work can position Perseus as essential to members
2. Identify milestones and comms moments in H2

Summary:

• It was agreed that:
  • IB1 should review member communications with a view to providing more regular, digestible, value-oriented summaries for members.
  • The group should better package engagement value for members, including parliamentary events, reports, and roundtables, so value is not framed only through technical progress.
  • The group should explore convening members to discuss how they maintain internal engagement and what support helps them make the case for Perseus internally.
• It was noted that:
  • The internal case for sustainability initiatives has become harder over the past 3–4 years, with executives sometimes finding reasons not to engage.
  • Members need to see short-term value from Perseus, such as visibility, knowledge, and connection, rather than only a long-term proposition.
  • The value case for Perseus needs to be calibrated to each member organisation’s priorities, which differ across firms.
• It was discussed that:
  • Perseus should position itself as business-critical and “must-have” for members.
  • There is a need for Perseus to equip members to sell the proposition internally with evidence of immediate value and organisation-specific messaging.
  • Perseus could seek to build more external prestige. Co-branding with members’ research, events, and outputs might help.
  • Perseus-convened roundtables with micro-businesses were a practical benefit for many members.

Next meeting: Thursday 8th October 2026 10:00-10:40 BST

Formal records, including attendees, are maintained by the secretariat. 

These are confidential to the Advisory Group Members.

Meeting Aims:

1. Illustrate the SME journey to a loan 
2. Update members on FCA and Perseus for Domestic discussions
3. Endorse initiative to reduce friction for SMEs to prove their address 

Summary:

It was agreed that:

• Immediate focus remains on real-world SME case studies and proving that banks can implement Perseus with their customers.
• While the business case for Perseus is clear (as per 2024 and 2025 annual reports), the internal investment cases must show material progress from the Perseus Members
• The Secretariat will continue to engage with the FCA, including preparing an updated briefing note on the potential impact of regulatory clarification.
• A working group will be formed to explore ways to streamline SME smart data access.

It was noted that:

• Perseus has been featured in DBT’s Smart Data Strategy. Discussions with DBT are positive and ongoing.
• The FCA has indicated that it can explore the potential of becoming an observer on the Perseus SG.
• From a measurement methodology perspective, there is a need for a minimum-viable, harmonised carbon intensity metric (potentially linked to revenue or EBITDA) that would meet baselining needs, but not compete with existing industry and commercial scoring models.

It was discussed that:

• From a regulatory perspective, a tension has been identified between the potential interpretation of FCA rules and banks’ perceived ability to proactively reach out to customers on climate finance. Members discussed the potential  impacting of this on the perceived size of the addressable market. This discussion helped frame inputs into the briefing note.
• From an impact perspective, smart meter data could support broader customer engagement: nudges, insights, and efficiency recommendations, not just finance offers.
• From an opportunity perspective, there is potential for Perseus (for SMEs) to expand into the domestic market (Perseus for Domestic), potential links with the Warm Homes Plan.

Next meeting: Monday 12 October 2026 10:00-11:30 BST

Formal records, including attendees, are maintained by the secretariat. 

These are confidential to the Advisory Group Members.

Meeting Aims:

1. Discuss member requirements for synthetic data in the Perseus sandbox
2. Evaluate what requirements existing for sandbox testing
3. Introduce and get feedback on the idea of a dev meetup

Summary:

It was agreed that:

• The Perseus team will formalise the existing readiness-check component into something members can use to demonstrate their integration is tested and working, building on roadmap work already under way.
• an autumn session will be organised, potentially in hackathon format, exploring how the sandbox could support AI coding agents and establishing what currently works.
• AG2 will set up a working group to design a structured approach for extending organisation role information held in the Directory, such as what data an energy data provider can supply.

It was noted that:

• The sandbox exists to let members verify their integration, build confidence ahead of live deployment, and test what cannot be tested in isolation, including correct handling of error responses. Out of scope: simulating system failures, load and performance testing, and standard authentication flows already covered elsewhere.
• Several candidate synthetic data sets exist: the Centre for Net Zero’s Faraday V5 (fully synthetic, modelled on real consumption with property and location parameters), the London Datastore (smaller, built to compare tariff changes), and Open Power System Data (domestic and small business consumption, though needing adaptation for Perseus).

It was discussed that:

• Smart data sharing is front of mind for one member, who described the market as blocked and in need of help to move forward.
• The suggestion that progress requires ICO enforcement or new legislation was not considered to be the best solution, as it relies on intervention from outside the market rather than action within it.
• Data protection uncertainty is often used as a reason to avoid progress altogether. Greater assurance on this point could remove a common blocker to engagement.
• There are concerns that RECCo’s purpose-agnostic approach to data sharing sits in tension with GDPR principles on the scope of permission granted.

Next meeting: Tuesday 6 October 2026 10:00-11:00 BST

Formal records, including attendees, are maintained by the secretariat. 

These are confidential to the Advisory Group Members.

Meeting Aims:

1. Discuss proposed SG member communication support
2. Gather AG4 advice and feedback on how to communicate the Perseus legal contract to members

It was agreed that:

• IB1 will revise the legal scheme structure slides to reflect the feedback from the group on the communications framing for the Perseus legal contract discussion.
• The revised version of the deck will be shared as an update at the next meeting rather than returning to this group for further review.
• The July meeting should be moved later in the month, extended to one hour, and positioned as a pre-summer wrap-up, with no meeting to be held in August.

It was noted that:

• Progress had been made in refining the approach to SG member engagement, including a shift from a one-size-fits-all approach to a more bespoke model of support for target organisations.
• The priority SG member targets remain the Federation of Small Businesses, British Chambers of Commerce, and Institute of Directors, reflecting their broad reach across UK business audiences.
• The legal contract communications material is intended to support more than one audience, including legal teams and wider senior or operational stakeholders within member organizations.
• The current visual presentation of the legal contract content appeared process-heavy and may be difficult for non-technical audiences to navigate.

It was discussed that:

• Efforts to mobilise SG members to use their voice to endorse and credentialise Perseus were underway, including the intention to produce tailored one-page briefs and build stronger relationships with communications teams over the summer.
• While legal review is an important part of the process, the broader value proposition for organisations lies in the opportunity to influence rules, implementation, and future scheme development.
• Communications materials should lead more clearly with the “why” and intended outcome, with clearer explanation of component parts and less reliance on process-led diagrams.
• Whether communications could be strengthened through references to existing precedents such as open banking, smart data schemes, and wider government direction of travel.

Next meeting: Thursday July 9th 2026 10:00-11:00 BST

Formal records, including attendees, are maintained by the secretariat. 

These are confidential to the Advisory Group Members.

Meeting Aims 

1. Review the emergent use cases and Perseus as a proof point
2. Agree on the go to market plan and addressable market
3. How to engage FCA to turn greenwashing regulation into an opportunity
4. Ensure our communications are consistent and reflect an agreed collective position

Summary:

• It was agreed that:
  • Perseus should continue its focus on ‘doing one thing well’ in 2026: delivering 5 SME case studies by the end of 2026.
  • The Q3 meeting (July 27th) will act as a key checkpoint ahead of the November meeting to assess whether year-end case study delivery is on track.
  • ‘Perseus for Domestic’ should be explored in a contained way so it does not distract from the core SME focus.
  • SG members should increase communications activity on Perseus, with IB1 providing tailored support, with priority outreach to identified members.
• It was noted that:
  • The Perseus member ecosystem now includes sufficient scope and reach to support an addressable market of over 1M UK SMEs.
  • At least one FSP is actively developing a higher-rate savings product tied to verified carbon intensity reductions: this is an example of live commercial product development within the membership.
  • Early FCA conversations are positive. IB1 has submitted a briefing note and will continue to engage.
  • Additional DOC members with governance or data expertise are requested.
• It was discussed that:
  • Perseus could be extended into domestic property use cases, particularly aligned to warm homes, retrofit and open property data. This could provide a timely collaboration between the Open Property Data Association, Open Banking Limited, and Perseus.
  • A blurred line exists between domestic and business energy use for home-based and hybrid-working SMEs, and there will be sensitivities around data sharing.
  • Perseus supports different strategic and communications priorities, including energy security and affordability, resilience, transition planning, adaptation and cost-reduction.
  • The incentives for SMEs will vary based on their circumstances (e.g. cheaper finance, preserved access to capital, lower reporting burden, and combinations of these).

Next meeting: Monday 27 July 2026 13:00-15:00 BST

Formal records, including attendees, are maintained by the secretariat. 

These are confidential to the Steering Group Members.

Meeting Aims:

1. Orientate for 2026
2. Agree workshops
3. Review market based carbon accounting concept

Summary:

It was agreed that:

• The Perseus team will circulate endorsable statements reflecting the positive intent and direction discussed, for communication to members and escalation to the steering group.

It was noted that:

• The commercial workshop produced positive outcomes, with EDPs willing to work on commercial terms, CAPs ready to scale and integrate, and FSPs continuing to see an active market.
• There are specific areas where regulatory and government engagement could help reduce friction in the current landscape that Perseus can assist with.
• Progress has been made on identifying lighthouse SME customer case studies, with both FSPs and CAPs

It was discussed that:

• Narrow, targeted case studies are needed first to generate proof points before broader scaling across the community.
• Typical delivery timelines are around two to three months for relatively straightforward use cases and around six months for more advanced ones.
• Water could be a possible next area of focus, with the view that it may be more accessible than agriculture in the near term, while agriculture remains important but highly complex.
• Exploration of extending a version of Perseus to the domestic market should be taken forward to a briefing note stage.
• Future opportunities included broader application into reporting, Scope 3, credit ratings, insurance, asset management, pensions, and risk modelling, though these were framed as longer-term possibilities rather than immediate priorities and that a roadmap should be developed for them.

Next meeting: Monday 29 June 2026 10:00-11:30 BST

Formal records, including attendees, are maintained by the secretariat. 

These are confidential to the Advisory Group Members.

Meeting Aims:

1. Update on onboarding flows
2. Discuss coding agents in relation to onboarding
3. Discuss automated compliance monitoring

Summary:

It was agreed that:

• Participants to send example queries and desired time ranges so the sandbox can be configured to return realistic test data.
• IB1 technical team to investigate synthetic data resembling real consumption patterns, alongside a deterministic dataset for automated emissions testing.
• Coding agent practitioners within participant organisations to be identified for further input on tooling and workflow.

It was noted that:

• Complete demo CAP flow is now available in the example app, with step-by-step guides for both CAP and EDP implementations.
• Single-step directory enrollment in progress; full API access to the directory planned.
• The sandbox EDP currently returns only ~3 days of February data, insufficient for monthly, quarterly, and annual reporting cycles and pure random synthetic data triggers anomaly detection and is not viable for testing.
• A heartbeat service is already included in the Perseus spec to check endpoint liveness and certificate validity.
• No SLA is currently in place for the sandbox; this is expected to change in production.

It was discussed that:

• Publishing skills alongside Perseus APIs is likely to significantly lower the barrier to integration when using AI coding tools.
• Agent authentication is an open design question; current thinking favours re-authenticating agents at each workflow stage rather than carrying a persistent token.
• Machine-parseable error messages and a separate agent sandbox were identified as priorities for AI-assisted integration.
• Compliance monitoring and operational/performance monitoring should be treated as distinct activities.
• In a federated peer-to-peer architecture, misbehaviour may only be apparent at points of interaction between peers; consideration needed on whether clients should be able to flag anomalies centrally.
• SMEs are out of scope for the Consumer Consent Solution at launch but expected to be included shortly after; no significant technical blockers identified.

Next meeting: Tuesday 30 June 2026 10:00-11:00 BST

Formal records, including attendees, are maintained by the secretariat. 

These are confidential to the Advisory Group Members.

Since the end of February, energy price volatility has been seen across multiple fuels, including oil and gas. And, while this volatility is being felt across the board, SMEs – which represent 99.85% of total business population and £2.8Tn in turnover – are being disproportionately exposed, particularly to sharp rises in gas prices.

For many SMEs, energy costs represent a meaningful share of operating expenses, particularly in sectors such as accommodation, retail, and food production. This leaves them more exposed to sudden price volatility, especially when access to tools and finance might be limited.

As costs rise, margins tighten and cash flow becomes less predictable, leading to increased uncertainty for both SMEs and lenders. For financial service providers – with over £68bn in SME lending portfolios – this shapes how risk is assessed and how capital is allocated.

At the same time, SMEs remain difficult to assess due to limited and inconsistent data. Rising uncertainty could push banks to tighten credit conditions across their portfolios, resulting in a feedback loop where SMEs face higher costs and reduced access to finance, while lenders carry greater uncertainty and risk.

Perseus provides a more complete view of energy costs

By expanding to include gas data, Perseus directly addresses this problem. In March 2026, the Perseus scheme began incorporating gas data, supporting calculations of Greenhouse Gas Protocol Scope 1 (direct) emissions alongside the Scope 2 (indirect) electricity emissions.

Moving beyond electricity to provide a more complete view of SME energy consumption and emissions gives SMEs better control over their energy exposure, while enabling banks to assess risk, verify impact, and finance the transition with greater confidence.

With this expansion, Perseus is estimated to have potential reach of over 1 million UK SMEs and cover over 70% of use cases, reflecting the scale of energy data across organisations.

For more on Perseus gas emissions methodology: https://ib1.org/perseus/emissions-calculations/ 

For SMEs, this means:

• reduced time, cost, and complexity of reporting
• a more complete and credible picture of energy use and emissions
• better access to finance and incentives
• potential for lower cost of borrowing

For banks and lenders, it enables:

• more accurate assessment of SME energy exposure
• improved risk pricing and credit decisions
• comparable, standardised data across portfolios
• the ability to develop targeted financing products linked to energy performance

Renewables over reliance

Reliance on fossil fuels remains a key driver of energy market volatility. It’s not an imagined scenario either, with Reuters recently reporting that wind output in Q1 2026 increased significantly year-on-year, helping to drive a ~16% drop in gas-fired generation. This cushioned the UK from the impacts of the gas price spike and contributed to relatively lower wholesale power prices versus some European peers. 

As more low-cost renewable electricity comes online, reliance on gas, and exposure to its volatility, can be reduced. This means the shift towards a cleaner renewable energy future is more than an environmental move but a financial one too, creating new opportunities for both SMEs and Financial Service Providers. 

While renewables can reduce our reliance on gas, flexibility determines how much of that value can actually be captured. For more on the impact I&C Flexibility can have on renewables take-up and the wider energy market, read our latest blog.

As Perseus co-chair, members, stakeholders, and the broader community tell me that it is seen as a pioneering initiative, with a significant scale of opportunity (at least £5B+ in embedded sustainable finance), but there are still challenges in communicating what it is, and isn’t, and ‘why now?’.

“Collaborate on the rules, compete in the game.”

The course is set, now it’s time to shape how value is realised

Perseus is now recognised as a flagship exemplar under the UK Data (Use and Access) Act, supported by both the Smart Data Council (in its Smart Data Strategy for 2035) and the Net Zero Council. The regulatory current is moving in this direction, and the Perseus team is both in constructive conversations with regulators and code bodies, and at the table in creating the UK Smart Data guidebook. 

Perseus Members are defining where the rules of embedded sustainable finance are being written. The question isn’t whether this infrastructure gets built, it’s who helps shape it, and who arrives late.

To help better position what Perseus is, here are some of my reflections, based on 300+ conversations.

Getting the data to do the work: SME impact at market scale

SMEs are where the impact is needed (they are half of UK business emissions). For the vast majority, carbon reporting is a burden: manual, confusing, inconsistent, and disconnected from anything that actually helps them run their business better. 

Perseus flips this: with the SME’s permission, their energy data flows automatically into their accounting platform and to their lender. No spreadsheets, no data entry, no consultants: they get a verified emissions baseline, access to sustainable finance products they can’t easily reach, and a credible sustainability story they can use with their own customers and suppliers. 

Perseus meets them where they are, through the tools and relationships they already have, and costs them almost nothing to participate. Reducing friction and cost is the point of good data infrastructure, getting smart data to do the work so the SME gets the benefits, and the market gets the scale. 

Perseus is infrastructure, not a product

Most responses to addressing SME carbon emissions follow a familiar playbook: build an app, sign up users, grow a dataset, and sell reporting services. Some go further and package insights as a commercial proposition. Both hit the same ceiling: they create value for their own customers, but they don’t change the market.

“Carbon reporting can often be seen as a random number generator linked to compliance, not value.”

Data silos are no longer business moats

When data stays siloed and calculations stay inconsistent, every bank, accountant, lender, software provider keeps solving the same problem independently, at their own cost. Multiply that across the whole economy and you have a colossal, systemic waste of time and money: with no true comparability, little trust, and no efficiency of scale. As one senior expert put it, “it’s a random number generator linked to compliance, not value“.

“Perseus meets SMEs where they are, through the tools and relationships they already have, and costs them almost nothing to participate.”

Perseus takes a structurally different route (the same route Open Banking took). The design of Open Banking wasn’t to ‘make a better banking app’, it was that if you agree the rules by which data flows between any bank and any third party, every player in the market benefits simultaneously, and the infrastructure becomes self-reinforcing as more join.

Perseus applies exactly that logic to SME emissions data: not a pipe, not a platform, a Scheme. A Scheme is a shared rulebook that defines how the data flows, it is legally permissioned, technically assured, and provenance-stamped between energy data sources, carbon accountants, and lenders, regardless of which specific providers are involved.

Schemes are designed to ‘do as little as possible’ so that the heavy lifting that they do deliver, can deliver at scale. Perseus is not a database, or a calculator, or a portal. Instead it’s the trust layer that makes everyone else’s products work together, enables solutions to go to where the customer already is, and makes them credible due to the governance wrapped around its design.

“Perseus is not a database, or a calculator, or a portal. It’s the trust layer that makes everyone else’s products work together.”

No single organisation can build what Perseus builds collectively

Any carbon accounting platform can reach its existing customers, any energy data business can find organisations already looking for a data feed, any bank can bring these things together, but none of them can, on their own, shift the behaviour of 5.5 million SMEs and the financial system that serves them.

Perseus can because its Steering Group and commercial membership collectively represent the whole system: the banks, accountants, energy companies, trade associations, and SME platforms that already have the customer relationships. The joint communications that can flow from this coalition don’t just amplify awareness, or make ‘business today’ more efficient, it creates an addressable market that didn’t previously exist. By going far together, they can all reach SMEs who have never considered net zero was for them, through channels they already trust: their bank, their accountant, their software tools, and their trade association. Perseus is creating a route to market no individual organisation can replicate through its own sales effort, and this is estimated to be £5B-£10B by 2030 (see 2025 annual report).

Its benefits can compound in both directions: automating data flows that currently require manual effort, reducing the cost of compliance, reducing friction at every point in the chain and building customer trust not for one product, but at market scale.

“Perseus Members are defining where the rules of embedded sustainable finance are being written. The question isn’t whether this infrastructure gets built, it’s who helps shape it, and who arrives late.”

The value case for a Financial Services Provider (e.g. bank, lender)

There are reasonable objections a bank or lender might raise. Right now, Perseus is a UK SME Scheme, not where the biggest financed emissions numbers sit for most large institutions; they may have existing bilateral data arrangements they’re reluctant to revisit; and in a climate where public sustainability commitments are under scrutiny anything that looks ‘new’ can face internal resistance. 

These are valid questions, but they don’t change the underlying logic.

In impact, most initiatives measure engagement, they rarely measure or report on verifiable impact. Perseus enables continuous, assurable measurement, reporting and verification of impact. By harmonising the approach, the reporting is comparable across organisations.

On scale: the UK SME market is not a rounding error but half of all UK business emissions. Any lender with a material SME book has a financed emissions reporting problem that carries sufficient risk to increase their cost of capital. Perseus addresses this across the whole market at once. Perseus Members have indicated that ‘just’ energy (electricity and gas) addresses over 70% of their use cases, and the programme is designed to expand beyond energy based on Member needs (e.g. water). If we go far together, our collective impact is material and meaningful.

On existing bilateral arrangements: Perseus doesn’t replace them, it improves them through harmonisation of approach, liability and technical provenance. Joining doesn’t unwind existing relationships, rather it gives them an additional trust layer, aligned with the Data Act and endorsed by the Net Zero Council.

On the commitment: Perseus is not a ‘climate pledge’, but an action to deliver the data infrastructure for embedded sustainable finance. Operationally, it’s equivalent to joining any financial data scheme – a technical and commercial decision, not a public statement about net zero ambition. It supports diverse go-to-market impact messaging across cost savings, energy efficiency, energy security, net zero and transition planning. It’s not a campaigning approach, but rather a way to deliver measurable value to the market.

“Any lender with a material SME book has a financed emissions reporting problem that carries sufficient risk to increase their cost of capital.”

On governance and legal overhead: Perseus’ architecture is deliberately modelled on Open Banking. Its legal agreements, certificate infrastructure and KYC processes are designed to align with what regulated financial institutions already do (the path through legal and compliance is not trivial, but it is well-trodden).

Ultimately, the financial providers already in Perseus are sitting in the room where the rules of sustainable finance data infrastructure are being written. It is a choice to be a late adopter of a model that Perseus members helped design, for a membership fee and some internal process. The cost of joining later is accepting the rules written by others.

The value case for a Carbon Accounting Providers (whether financial or carbon management)

A CAP might ask: why do we need Perseus? (we already have integrations with energy data providers, have bank and lender customers, and are building the product that does this).

These are fair points, but miss what Perseus is.

“Perseus is not a database, or a calculator, or a portal. It’s the trust layer that makes everyone else’s products work together.”

Every CAP currently solving this problem is solving it alone: each has negotiated its own data access arrangements, built its own ingestion pipelines, made its own judgements about data quality, and written its own terms. The result is a market where every emissions calculation is done differently, every audit trail looks different, and no two outputs are directly comparable. That’s not a CAP problem to fix, it is a market structure problem, and no single CAP can fix market structure.

This has been the case for decades. Now the baseline calculation needs to become pre-competitive infrastructure (co-designed and delivered by the market) so that CAPs can compete on the value they build on top of it.

Collaborate on the rules, compete in the game

Perseus addresses this by establishing a common trust layer (common legal agreements, provenance standards, assurance levels, harmonised calculations) so that data flowing into any Perseus-connected CAP is verified, traceable, and comparable to data flowing into every other. This doesn’t commoditise the CAP’s product, but rather makes the CAP’s product something an SME or bank can actually rely on, report against, and put in front of an auditor with confidence.

On distribution: joining Perseus is not just a technical integration but access to a network of lenders, trade associations and SME platforms that collectively reach the entire UK SME market. This is a route to market no CAP can replicate through its own commercial efforts. Perseus-connected CAPs are not just selling software but access to a trusted, standards-aligned data flow that their competitors outside the scheme cannot match.

On the competitive question: the CAPs already building Perseus integrations reach hundreds of thousands of UK SMEs today. They are not waiting before positioning themselves within it. Waiting until Perseus is ‘already proven’ before engaging will find the integrations, the relationships, and the market positioning is already occupied.

On effort: Perseus adds a compliance overhead, but this is inversely proportional to scale. The cost of integrating once (which can be done in under a month) with a common framework is substantially lower than maintaining multiple bespoke bilateral arrangements as the market grows. Perseus reduces long-run complexity, it doesn’t add to it.

Spend-based estimates or manually uploaded spreadsheets are no longer fit-for-purpose. Perseus provides the foundations that CAPs can build on top of, creates trust, defensibility, reduces long-term costs, increases market engagement and innovation.

To go far, we go together.

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Meeting Aims:

1. Update on case studies
2. Discuss upcoming actions
3. Review Vision statement

It was agreed that:

• British Chambers of Commerce, FSB and IOD should be prioritised as strategic targets to help amplify comms due to their credibility, authority and member reach
• The updated Perseus’ vision and mission statement should be approved

It was noted that:

• Innovate Finance’s Global Summit is in April and panel opportunities on sustainable energy featuring Perseus maybe available
• London Climate Action Week takes place in June and IB1 has a cross-sector meetup planned
• One of the members has two potential SME contacts who might be able to contribute, both PR-ready having presented at the Houses of Parliament

It was discussed that:

• The geopolitical context presents a timely opportunity to amplify Perseus messaging, particularly around energy sovereignty, the government’s consideration of decoupling gas/electric price caps, and the cost of living crisis
• Small businesses are being significantly impacted by energy costs, national insurance increases, minimum wage changes and inflation, making Perseus a relevant operational efficiency solution
• In order to achieve amplification, there is a need to identify the right internal spokespeople within steering group member organisations, not just the steering group representatives themselves

Next meeting: Thursday 28 May 2026 10:00-10:45 BST

Formal records, including attendees, are maintained by the secretariat. 

These are confidential to the Advisory Group Members.

• twenty interoperable Smart Data schemes by 2035
• £36m of Industrial Strategy investment
• cross-sector Trust Frameworks and data sharing interoperability across the economy

https://www.gov.uk/government/publications/smart-data-strategy

For IB1, this is core to our work – and features the Perseus programme. It underpins how we will help deliver our sustainable economy into a data-enabled digital-first era, building the load-bearing foundations for trust, protecting our data rights, and delivering impact.

Open Banking took a decade to get right: we can now move much, much faster. The opportunity isn’t just ‘switching’, it’s opening up new markets and connecting financial flows to real-world outcomes at scale. The time to engage is now: the schemes being shaped today will define the data infrastructure of the next decade.

The UK has a great team helping to lead this, with Samantha as co-chair, the Department for Business and Trade (Siobhan, Agnieszka, Priya, and a growing support team), and non-govt Smart Data Council members including Henk, Adam, Liz, Charlie, Marie, Chris, Ezechi, Ghela, Helen, Joe, Josh , Louise, Maria, Nicola, Stephen, Jane, Lucy, Sue and many others across industry and government now engaged.

At Icebreaker One it’s what we’ve been building with IB1 Open Energy Perseus, STREAM and our Data Infrastructure work and we will continue to lead on Open Sustainable Finance.

Meeting Aims 

1. Agree on updated vision and mission
2. Understand 2026 roadmap
3. Update on DOC and AG
4. Commit to amplifying case studies
5. Identify funding sources

Summary:

• It was agreed that:
  • Case studies are the critical success metric for 2026. The ambition is to secure at least five examples that demonstrate real-world application.
  • Alignment with the Net Zero Council and the Smart Data Council agenda should continue, positioning Perseus as an exemplar of Smart Data implementation and Net Zero innovation.
• It was noted that:
  • The 2025 AGM reflected strong engagement from key stakeholders and financial service providers (including incumbents NatWest, Barclays and Lloyds and challenger banks).
  • Language has evolved to “embedded sustainable finance”, with continued emphasis on SME impact.
  • Sandbox learnings (AG2) identified and resolved integration challenges (e.g. with certificate authentication, improved documentation and clarity of roles, setup guides, tooling and specifications have been developed in response).
  • Legal updates (AG3) incorporate gas into permission text, clarify CAP-initiated (two-click) and FSP-initiated (single-click) consent journeys; Scheme agreement documentation has been consolidated; changes remain compliant with prior external legal advice.
  • Annual renewals remain the current funding model, with forecast renewals on track but cashflow risk recognised and multi-annual renewals should be considered.
  • The relationship with B4NZ (formerly ‘Bankers for Net Zero’) was recognised as having been supportive in the formation of the programme, and there is no ongoing relationship with that initiative.
  • Adam Jackson has accepted the role of DOC Chair.
• It was discussed that:
  • The proposed new vision, “Embedded sustainable finance for SMEs”, provides a clear and memorable direction of travel. Further refinement of mission language will be considered to ensure terminology resonates with SMEs.
  • The SME focus remains strategically valuable for maintaining clarity and discipline. Discussion included whether anchoring exclusively on SMEs may constrain broader use cases and it was noted that related initiatives (e.g. ib1.org/Orion and ib1.org/carbon-commons) had been created as channels to help develop ideas without distracting from Perseus’ core mission.
  • Case study development faces practical barriers: delays often arise from internal processes and time constraints, rather than inherent SME reluctance. It was noted that the majority SMEs day-to-day concerns are focussed on cash, not sustainability, and that Perseus’ strategy to reduce both cost and friction for SMEs (including ‘taking solutions to where the SME already are’) was the correct approach.

Next meeting: Monday 18 May 2026 13:00-15:00 BST

Formal records, including attendees, are maintained by the secretariat. 

These are confidential to the Steering Group Members.

Meeting Aims:

1. Summarise Sandbox learnings
2. Feedback from members on Perseus-ready integration
3. Discuss change management best practice
4. Present draft certificate revocation specification
5. Explore workshop topics in 2026

Summary:

It was agreed that:

• Lessons from sandbox integrations would continue to inform incremental improvements to documentation, tooling, and processes.
• Future change proposals would aim to present technical changes more concretely, including clearer linkage between definitive specifications, and registry entries.

It was noted that:

• Four categories of issues had emerged from recent sandbox integrations:
  • Certificate authentication challenges, including confusion around directory usage and certificate expiry on services.
  • Conceptual understanding gaps, particularly around the FAPI 2 security model and Perseus’ role as an enabler of connections rather than a data provider.
  • Areas where documentation required clarification, including subdomain queries, CAP-to-EDP selection, and OAuth flow setup.
  • Technical usability issues with the directory service, including sandbox labelling and endpoint behaviour.
• A range of documentation and support improvements had been implemented in response, including workflow diagrams, role-specific setup guides (CAP and EDP) , a CLI testing tool for EDPs, and a directory usage guide with screenshots.

It was discussed that:

• IB1 recommends a Certificate Revocation List (CRL) approach over OCSP for certificate withdrawal, on the basis of simplicity, lower operational complexity and improved privacy characteristics; we are accepting review and feedback on this until February 27 (see actions)
• Git-based workflows were seen as helpful for proposing and reviewing technical changes (such as API updates), but not sufficient on their own to describe multi-environment availability or long-term governance state.
• Future change proposals could benefit from clearer presentation of “before and after” states, including diffs against OpenAPI specifications, supported by explanatory documents.

Next meeting: Tuesday 28 April 2026 10:00-11:00 GMT

Formal records, including attendees, are maintained by the secretariat. 

These are confidential to the Advisory Group Members.

Meeting Aims:

1. Orientate for 2026
2. Agree workshops
3. Review market based carbon accounting concept

Summary:

It was agreed that:

• The primary focus for the year ahead is on concrete customer use cases and case studies.
• Individual follow‑ups will be undertaken with Members to map internal stakeholders and decision‑making processes.
• Each Member will prioritise identification of at least one potential ‘lighthouse’ customer.
• Further work will document and consult on the proposed market‑based emissions methodology, including supporting FAQs.

It was noted that:

• 2026 is the key go‑to‑market period, translating existing technical capability into demonstrable customer value.
• Constructive early conversations have taken place with the Financial Conduct Authority regarding Perseus’ positioning with Smart Data/Open Finance initiatives.
• to broaden scope beyond lending to include savings, asset finance, and other financial products, the phrase “access to finance” has evolved to “financial incentives”
• £5–10bn potential addressable  market is seen as ‘directionally credible’ and indicates substantial value opportunities for all stakeholders.

It was discussed that:

• From an SME perspective, particularly micro‑businesses, sustainability and net zero language has limited traction
• SMEs prioritise cost reductions, operational efficiency, and resilience, with emissions reduction often viewed as a secondary benefit. Perseus’ position as embedded sustainable finance is tactically aligned with this. 
• A key opportunity to increase TAM is ‘taking incentives directly to where the SMEs are’ (i.e. in their accounting and analysis applications) 
• Large financial institutions face material internal constraints, with implementation timelines often measured in years rather than months
• Technology is not the primary blocker; the key gap lies in the business case and incentive structures and this will inform our go‑to‑market approach, and clarity of financial value.

Next meeting: Monday 20 April 2026 10:00-11:30 GMT

Formal records, including attendees, are maintained by the secretariat. 

These are confidential to the Advisory Group Members.

Meeting Aims:

1. Understand the Perseus 2026 Roadmap
2. Feedback from the AGM
3. Sign off a 2026 comms plan

Summary:

It was agreed that:

• 2026 comms will pivot more strongly to detailed, high‑quality case studies as a central tool to build trust and drive membership, rather than relying primarily on generic messaging or high‑level testimonials.
• The co-chair will share existing best‑practice case‑study and member‑spotlight formats she has developed (at Tide) with the IB1 team to inform Perseus templates.

It was noted that:

• The Perseus AGM was positively received
• The core comms outcomes for 2026 remain: Building trust and confidence in Perseus and making a consistent, compelling case for new and renewed memberships
• The communications plan for 2026 was presented and agreed
• High‑quality, detailed case studies are better suited than broad messaging to demonstrate ease of integration, tangible benefits, and business value.

It was discussed that:

• Perseus’ vision and mission will evolve in 2026, with suggestion by one member that this ought to be amended to also highlight benefits
• New case‑study formats could include a multi‑part journey following one CAP across the year
• Physical/in‑person or live formats (e.g. roundtables, workshops) can generate richer engagement and large amounts of reusable digital content

Next meeting: Thursday 26 March 2026 10:00-10:45 GMT

Formal records, including attendees, are maintained by the secretariat. 

These are confidential to the Advisory Group Members.

At the Perseus 2025 AGM it was reported that Perseus is:

• evolving from ‘financing green’ to embedded sustainable finance creating a potential addressable market of £5-10 billion
• adding gas, extending energy coverage from Scope 2 (electricity) to Scope 1
• estimated, via its existing members, to have potential reach of over 1 million UK SMEs and cover over 70% of use cases
• continuing to advance ‘Perseus Ready’ implementations with commercial members
• running a live sandbox (equivalent to production) for use by Carbon Accounting Providers (CAPs) and Energy Data Providers (EDPs) to develop solutions
• working with Perseus members to develop go-to-market capabilities to support hundreds of thousands of SMEs
• exploring integration with Open Banking to enable cross-sector interoperability
• producing XBRL outputs to enable integration with financial reporting systems
• pioneering the development of a voluntary, cross-sector Smart Data scheme, aligned with the UK Data Act and supported by an openly-licensed digital public infrastructure (DPI) architecture for secure data sharing 

“Perseus makes it easier for everyone to do their carbon calculations properly, and comfortably moves us years ahead of the most stringent proposed updates to the GHG Protocol. This is exactly why Sage intends to roll out a Perseus enabled product to make reporting easier for hundreds of thousands of UK SMEs.”

George Sandilands, Vice President, Sage Earth

From financing green to embedded sustainable finance

For much of the last decade, ‘green finance’ has focused on funding individual projects: a retrofit here, a solar installation there. Important, but limited. 

Perseus marks a shift to something far more systemic: it moves beyond financing green to embedding sustainable finance by integrating trusted, verifiable emissions data directly into everyday accounting and financial decision-making.

This evolution means Perseus can be applied across the whole SME market, not just specialist green products. Rather than expecting SMEs to seek out solutions themselves – something most lack the time or expertise to do – Perseus brings trusted insights to where they are (e.g. inside their existing accounting, banking and carbon applications). 

Perseus can support lending, credit and debit products, and even savings accounts, allowing sustainability performance to be reflected wherever financial decisions are made. The impact on SMEs is significant: personalised insights, lower reporting costs, easier access to capital for energy-efficiency upgrades, and new space for financial innovation. By making sustainability data usable at scale, Perseus aims to help turn ‘net zero’ from a niche ambition into a normal feature of how the economy works.

“As a leading smart data initiative, Perseus is developing guardrails for assurable data to support finance and supply chain decisions towards a sustainable economy.”

Hannah Gilbert, Director of Sustainability, British Business Bank