UK Government Endorses ISSB Standards for Sustainability Reporting

February 2026 endorsement creates unified disclosure framework

The UK Department for Business and Trade published the UK Sustainability Reporting Standards on 25 February 2026. The move brings coherence to a reporting landscape that has, until now, required businesses to navigate separate obligations under SECR, TCFD, and ESOS. For the first time, large and listed companies will work within a single framework built on global standards.

The UK SRS consist of two standards. S1 establishes general requirements for disclosing sustainability-related risks and opportunities. S2 focuses specifically on climate, covering physical and transition risks, greenhouse gas emissions across all three scopes, scenario analysis, and transition plans. Both standards derive from the International Sustainability Standards Board’s IFRS S1 and S2, adapted for UK application following consultation with businesses, investors, and professional bodies.

Initially, any entity can adopt the standards voluntarily. However, mandatory requirements are coming. The Financial Conduct Authority has proposed that listed companies must comply with S2 from 1 January 2027, with S1 following in stages. Transitional reliefs will give companies time to build the necessary data collection and assurance processes, particularly for Scope 3 emissions and non-climate disclosures.

This represents the end of fragmented reporting and the beginning of a system designed for comparability. The implications stretch beyond compliance departments into board strategy, investor relations, and supply chain management.

Three years of development produced the final standards

The ISSB issued its inaugural standards on 26 June 2023. These became the foundation for what the UK would eventually endorse. However, the path from international standard to domestic regulation involved several stages of adaptation and consultation.

In December 2024, the Technical Advisory Committee recommended endorsement of IFRS S1 and S2 with specific UK modifications. These included flexible application dates and the option to use industry classifications beyond the Global Industry Classification Standard. The modifications acknowledged the practical realities facing UK businesses while maintaining alignment with the global baseline.

By June 2025, DBT had published exposure drafts of UK SRS S1 and S2. A public consultation ran from 25 June to 17 September 2025, gathering views on the draft standards and proposed assurance oversight arrangements. Feedback summaries were released later that year, informing the final versions published in February 2026.

In January 2026, DBT wrote to the FCA regarding implementation timelines and transitional reliefs. This correspondence set out how listed companies would transition from existing TCFD-aligned disclosure rules to the new UK SRS framework. The letter clarified that S2 would be prioritized, with companies required to report on climate before tackling the broader sustainability topics covered by S1.

The FCA opened its own consultation on amendments to UK Listing Rules on the same day the standards were published. That consultation will close on 20 March 2026. Responses will shape how the regulator applies the standards to listed entities and what flexibilities will be available during the transition period.

S1 covers governance, strategy, and risk management processes

UK SRS S1 establishes the foundation for sustainability disclosure. It requires companies to report on four core areas: governance, strategy, risk management, and metrics and targets. These disclosures must focus on sustainability-related risks and opportunities that could reasonably affect the entity’s prospects.

Governance disclosures explain how boards and management oversee sustainability matters. Companies must describe the processes, controls, and procedures they use to monitor and manage these issues. Strategy disclosures identify which sustainability-related risks and opportunities could affect business model, value chain, or financial position over the short, medium, and long term.

Risk management disclosures detail how companies identify, assess, and respond to sustainability-related risks. This includes integration with overall risk management processes. Metrics and targets must be specific, measurable, and connected to identified risks and opportunities. Where industry-specific metrics exist, companies should use them to enable comparison.

S1 applies to all material sustainability topics, not just climate. This means companies will eventually need to consider water, biodiversity, social factors, and other issues. However, the phased implementation approach means climate reporting under S2 takes priority initially. Non-climate disclosures under S1 will follow, with a two-year transitional relief period allowing companies to build capacity gradually.

S2 mandates specific climate-related financial disclosures

UK SRS S2 focuses exclusively on climate. It requires detailed disclosure of climate-related risks and opportunities using the same four-pillar structure as S1: governance, strategy, risk management, and metrics and targets. However, S2 goes further by specifying what must be included.

Physical risks might include flood damage to facilities, supply chain disruption from extreme weather, or increased cooling costs. Transition risks cover policy changes, technological shifts, market dynamics, and reputational factors. Companies must explain how these risks could affect their financial position and performance.

Greenhouse gas emissions reporting is mandatory under S2. Companies must disclose Scope 1 emissions (direct emissions from owned or controlled sources), Scope 2 emissions (indirect emissions from purchased energy), and Scope 3 emissions (all other indirect emissions in the value chain). Scope 3 often represents the largest proportion of a company’s carbon footprint, covering purchased goods, transport, use of sold products, and end-of-life treatment.

Scenario analysis helps companies understand resilience under different climate futures. S2 requires analysis using at least one scenario aligned with limiting warming to 1.5°C above pre-industrial levels. Companies must also disclose transition plans explaining how they will adapt business models and operations to address climate risks and support a lower-carbon economy.

Consequently, S2 creates a rigorous baseline for climate disclosure. The financial linkage requirement means companies cannot treat climate as a separate non-financial issue. They must show how climate factors connect to assets, liabilities, revenues, expenses, and cash flows.

Mandatory application begins January 2027 for listed companies

The UK SRS are currently available for voluntary adoption by any entity. This allows early movers to test processes and build internal capability before mandatory deadlines arrive. However, the government and FCA have made clear that requirements will become compulsory for certain companies.

Listed companies face the first mandatory deadline. The FCA has proposed that entities with a premium or standard listing must comply with UK SRS S2 for financial years beginning on or after 1 January 2027. This climate-first approach recognizes that many listed companies already report under TCFD-aligned rules and have some infrastructure in place.

S1 will be phased in for listed companies after S2. The government has not yet specified exact timelines for unlisted large companies, but legislation is expected to follow. In the meantime, existing obligations under SECR and FCA disclosure rules remain in force until the full transition to UK SRS is complete.

Transitional reliefs provide breathing space for complex areas. Companies will have one year to comply with Scope 3 emissions reporting on a comply-or-explain basis. This acknowledges the data challenges involved in measuring emissions across supply chains, particularly for businesses with complex international operations. Non-climate disclosures under S1 receive a two-year relief period, allowing companies to develop measurement and reporting systems for broader sustainability topics.

Third-party assurance is coming but not immediately. The government expects companies to obtain limited assurance over their sustainability disclosures in due course. However, this requirement will be phased to give the assurance market time to develop capacity and companies time to prepare robust data collection processes.

Key points about the new standards

• UK SRS S1 and S2 were published on 25 February 2026, based on ISSB’s IFRS S1 and S2 with UK-specific modifications.
• Listed companies must comply with S2 from 1 January 2027 under proposed FCA rule changes, with S1 phased later.
• S1 covers general sustainability risks and opportunities across governance, strategy, risk management, and metrics.
• S2 requires climate-specific disclosures including Scope 1, 2, and 3 emissions, scenario analysis, and transition plans.
• Transitional reliefs provide one year for Scope 3 emissions and two years for non-climate disclosures under S1.
• The standards replace fragmented obligations under SECR, TCFD, and ESOS with a unified framework.
• Voluntary adoption is available immediately for any entity preparing for mandatory requirements.

Supply chains and procurement create immediate pressure points

The Scope 3 requirement will force many businesses to examine their supply chains more closely than ever before. Purchased goods and services typically represent the largest category of Scope 3 emissions for manufacturers, retailers, and construction companies. Measuring these emissions requires data from suppliers about their own operations and energy use.

Many SMEs will find themselves fielding requests from larger customers who need Scope 3 data to meet their own reporting obligations. This creates a cascading effect through supply chains. Businesses that cannot provide credible emissions data may find themselves at a disadvantage when competing for contracts with companies reporting under UK SRS.

Public sector procurement already places weight on carbon reduction through PPN 06/21, which requires suppliers bidding for large contracts to publish a carbon reduction plan. The new standards will reinforce this trend in private sector procurement. Buyers will want to understand the emissions profile of their supply base, and they will favor suppliers who can provide transparent, verified data.

The standards also affect how companies think about their own products and services. Scope 3 includes use of sold products and end-of-life treatment. A vehicle manufacturer must consider emissions from cars being driven. A software company must account for energy consumed by data centers running its applications. This pushes sustainability considerations into product design and business model innovation.

Moreover, companies with international operations face complexity around data collection across multiple jurisdictions. Different countries have different emissions factors, reporting standards, and data availability. Building systems to gather, verify, and consolidate this information requires investment in technology and skills. The transitional relief for Scope 3 provides time, but preparation should start now.

Financial materiality connects sustainability to business value

The UK SRS apply a financial materiality lens. Companies must disclose sustainability information that could reasonably influence the decisions of primary users of financial statements. This differs from the impact materiality approach used in some other frameworks, where the focus is on the company’s effect on the environment and society.

Financial materiality means companies must show how sustainability factors connect to enterprise value. A carbon-intensive manufacturer might face higher costs if carbon pricing expands. A food business might see margin pressure if water scarcity affects agricultural supply chains. A financial services firm might face credit losses if climate risks materialize in its lending portfolio.

This approach integrates sustainability into mainstream financial reporting. Investors can use the information to assess risks and opportunities affecting long-term returns. Lenders can factor climate and other sustainability risks into credit decisions. Insurers can better understand exposures in their underwriting portfolios.

However, financial materiality creates assessment challenges. Companies must judge which sustainability matters could affect their financial position over time. This requires understanding transmission mechanisms: how a physical climate event translates into business disruption, how a policy change affects cost structures, how reputational factors influence customer behavior.

Scenario analysis helps with this assessment. By modeling business performance under different climate scenarios, companies can identify vulnerabilities and test strategic responses. The requirement to use at least one 1.5°C scenario ensures companies consider a future where policy and technology change rapidly to limit warming.

Board accountability and governance expectations increase

The governance pillar of both S1 and S2 places clear expectations on boards and executive management. Companies must disclose who is responsible for oversight of sustainability matters, how often these topics are reviewed, and how they inform strategy and decision-making.

This moves sustainability from the corporate responsibility team to the boardroom. Directors must understand the principal sustainability-related risks facing the business and how management is responding. Audit committees will need to oversee the reliability of sustainability data with the same rigor they apply to financial information.

Remuneration committees may find sustainability metrics increasingly linked to executive pay. If companies set public targets for emissions reduction or other sustainability outcomes, investors will expect accountability through compensation structures. This creates pressure to ensure targets are credible, measurable, and aligned with science-based pathways.

The standards also require disclosure of skills and competencies. Boards must explain how they ensure sufficient expertise to oversee sustainability matters effectively. This may drive demand for non-executive directors with climate science, environmental, or sustainability credentials. It may also prompt companies to provide training for existing board members.

Furthermore, the connection between sustainability and risk management becomes explicit. Companies must describe how they integrate sustainability-related risks into overall risk management processes. This includes identifying which risks could have material financial effects and how they are monitored and mitigated.

Assurance and data quality will require investment.p>

Third-party assurance over sustainability disclosures is expected but not yet mandatory. The government intends to phase in assurance requirements, recognizing that the market needs time to develop capacity. However, companies should anticipate that investors and other stakeholders will increasingly demand verified information.

Limited assurance represents the likely starting point. This provides moderate confidence that information is free from material misstatement, similar to a review of interim financial statements. Over time, requirements may move toward reasonable assurance, which provides a higher level of confidence and is comparable to a full financial statement audit.

Assurance creates pressure to improve data quality and internal controls. Companies must document methodologies, retain evidence, and demonstrate consistent application of measurement approaches. This is straightforward for Scope 1 and 2 emissions where data comes from energy bills and metering. It is far more challenging for Scope 3, which relies on estimates, supplier data, and industry averages.

Technology will play a role in managing this complexity. Carbon accounting software can help collect, calculate, and consolidate emissions data across multiple sites and geographies. Integration with financial systems ensures consistency between sustainability and financial reporting. However, software alone cannot solve data quality issues if underlying information is incomplete or unreliable.

Skills development is equally important. Finance teams will need to understand sustainability metrics and reporting requirements. Sustainability professionals will need to work within financial reporting controls and timelines. Cross-functional collaboration becomes essential. Training programs covering carbon accounting, reporting standards, and assurance readiness can help businesses build the necessary capabilities.

Practical steps for businesses approaching the deadlines

Companies should start by assessing their current position. What sustainability information do you already collect and report? How does it map to UK SRS requirements? Where are the gaps? This baseline assessment helps prioritize areas needing investment and development.

Scope 3 emissions often represent the biggest challenge. Begin by categorizing your value chain into the 15 Scope 3 categories defined by the GHG Protocol. Identify which categories are likely material based on your business model. Focus initial effort on the largest sources, such as purchased goods and services, business travel, or use of sold products.

Engage suppliers early. Explain why you need emissions data and what information you require. Provide templates or guidance to make the process easier. Consider offering support to smaller suppliers who may lack internal resources. Building collaborative relationships now will make ongoing data collection more efficient.

Establish governance processes that bring sustainability into core decision-making. This might mean creating a board-level sustainability committee, adding sustainability as a standing agenda item for the main board, or linking executive incentives to specific targets. Governance is not just a disclosure requirement; it shapes how seriously the organization takes these issues.

Test your scenario analysis capability. Start with a simple climate scenario that explores how your business would be affected by carbon prices reaching £100 per tonne, or by a 2°C temperature rise by 2050. Identify which assets, products, or markets face the greatest exposure. Use this analysis to inform strategy discussions and capital allocation decisions.

Consider voluntary adoption before mandatory deadlines arrive. Early reporting allows you to identify practical challenges, refine data collection processes, and build stakeholder confidence. It also provides a baseline for measuring progress over time. Companies that wait until requirements are mandatory may find themselves rushing to meet deadlines with inadequate systems.

Professional support for carbon reporting and ESG compliance can accelerate preparation, particularly for businesses without in-house sustainability expertise.

How the UK standards fit with international reporting

The UK SRS are built on ISSB standards, which means companies reporting under UK SRS will produce disclosures comparable to entities using IFRS S1 and S2 in other jurisdictions. This matters for businesses with international operations, multinational investors, or cross-border supply chains.

Several countries have already adopted or announced plans to adopt ISSB standards. This creates potential for a global baseline of sustainability reporting, reducing the burden of preparing multiple reports for different jurisdictions. However, some regions have taken different approaches, most notably the European Union with its Corporate Sustainability Reporting Directive.

CSRD uses a double materiality approach, requiring companies to report both how sustainability matters affect the business (financial materiality) and how the business affects the environment and society (impact materiality). UK SRS focus only on financial materiality. This creates a divergence for UK companies operating in the EU, who may need to report under both frameworks.

Nevertheless, there is considerable overlap in the underlying data and disclosures. Emissions data collected for UK SRS will be relevant for CSRD. Governance structures and risk management processes described under UK SRS will inform EU reporting. The additional work for EU compliance relates mainly to impact assessment and broader stakeholder considerations.

Companies should monitor developments in other jurisdictions where they operate or have significant investors. The International Organization of Securities Commissions has endorsed ISSB standards, which may encourage more countries to adopt them. This would strengthen the case for using UK SRS as the foundation for all sustainability reporting, with jurisdictional supplements where required.

Where to find authoritative guidance and resources

The Department for Business and Trade published the final UK SRS on GOV.UK. The DBT website includes the full text of both standards, supporting documentation, and the government’s endorsement statement explaining how UK SRS relate to IFRS S1 and S2.

The Financial Conduct Authority is consulting on amendments to UK Listing Rules. The FCA consultation paper sets out proposed mandatory requirements for listed companies, transitional reliefs, and implementation timelines. Responses to this consultation will shape the final rules applying from January 2027.

The International Sustainability Standards Board provides extensive educational material on IFRS S1 and S2. The ISSB section of the IFRS Foundation website includes implementation guidance, illustrative examples, and webinars explaining how to apply the standards in practice.

Professional bodies offer sector-specific resources. The Institute of Chartered Accountants in England and Wales has published guidance on applying UK SRS in different industries. The Chartered Institute of Procurement and Supply provides resources on supply chain emissions measurement. These materials can help companies understand how general requirements apply to their specific circumstances.

Businesses preparing for mandatory reporting can also benefit from structured programs supporting carbon measurement and disclosure readiness, particularly where internal resources are limited or technical expertise needs to be developed quickly.