UK SRS S1 and S2 in plain English

UK SRS stands for the UK Sustainability Reporting Standards — two standards, not one. UK SRS S1 sets the general requirements for disclosing sustainability-related financial information; UK SRS S2 covers climate. Both were published by the Department for Business and Trade on 25 February 2026, endorsed from the ISSB baseline of IFRS S1 and IFRS S2 with six UK-specific amendments. They are voluntary for any UK entity today: UK SRS S2 is proposed to become mandatory for in-scope listed companies from 1 January 2027, and UK SRS S1 on comply-or-explain from 1 January 2029.

UK SRS S1 provides general requirements for disclosure of sustainability-related financial information covering all material sustainability topics except climate (biodiversity, water, workforce, supply chain, human rights, governance, resource use). It follows single (financial/enterprise-value) materiality on the ISSB/IFRS S1 basis and is proposed for mandatory comply-or-explain application from 1 January 2029.

UK SRS S2 covers climate-related disclosures using the four-pillar TCFD architecture (Governance, Strategy, Risk Management, Metrics & Targets). It's proposed for mandatory application to UK-listed companies from 1 January 2027, with Scope 3 emissions on comply-or-explain from 1 January 2028.

UK SRS S1 provides the architectural foundation (materiality, connectivity, value chain principles) that UK SRS S2 climate disclosures rely on. While UK SRS S2 is proposed to apply first (1 January 2027 under FCA CP26/5, subject to the autumn 2026 Policy Statement), UK SRS S1 concepts are essential for proper UK SRS S2 implementation. Companies cannot apply UK SRS S2 in isolation without understanding UK SRS S1 principles.

Under FCA CP26/5 proposals, UK SRS S2 becomes mandatory for in-scope listed companies from 1 January 2027, with Scope 3 emissions on comply-or-explain from 1 January 2028. UK SRS S1 follows on comply-or-explain from 1 January 2029. CP26/5 closed for consultation on 20 March 2026; the FCA Policy Statement confirming final rules is expected autumn 2026.

Approximately 515 UK-incorporated LSE-listed companies under UKLR 6, 14, 15, 16, and 22 are proposed for mandatory UK SRS S2 from 2027, followed by UK SRS S1 from 2029. Private companies remain under review via the Modernising Corporate Reporting (MCR) programme with DBT consultation expected later in 2026. Any UK entity can voluntarily adopt UK SRS S1 and S2 now.

The UK made six key amendments to IFRS S1 for UK SRS S1: (1) UK effective dates replace ISSB references, (2) first-year transitional relief removed, (3) climate-first relief reworked to match UK phasing, (4) SASB 'shall' softened to 'may', (5) GICS classification requirement removed, and (6) connectivity to financial statements clarified for UK context. These amendments also impact UK SRS S2 implementation.

UK SRS S2 retains the four-pillar TCFD architecture but with enhanced disclosure requirements. The TCFD framework was formally disbanded in October 2023 and succeeded by ISSB standards which UK SRS adopts. UK SRS provides more prescriptive requirements than previous TCFD-aligned Listing Rules.

No mandatory assurance is proposed in the initial phase. Under FCA CP26/5, in-scope companies must disclose whether they have obtained third-party assurance (disclose-or-explain). UK practitioners use ISSA (UK) 5000 standards. The FRC maintains an interim Sustainability Assurance Register.

Yes, UK SRS S1 and S2 are available now for voluntary early adoption by any UK entity with all-or-nothing compliance required (no partial adoption). Early adoption requires a full statement of compliance with the chosen standard(s). Many companies are using the voluntary period for readiness testing.

UK SRS follows single materiality (investor-focused) while EU CSRD uses double materiality (investor + impact). UK SRS is based on IFRS S1/S2 with UK amendments, while ESRS uses a broader EU-specific framework. Both cover climate and broader sustainability topics but with different scopes and requirements.

The FRC provides guidance and maintains a practitioner assurance register. Professional bodies including ICAEW, ACCA, and CIMA offer training and resources. The government published detailed implementation guidance alongside the final standards.

Subject matter and timing. UK SRS S1 is the general standard: it covers every material sustainability topic except climate — biodiversity, water, workforce, supply chain, human rights, governance, resource use — and sets the reporting architecture (materiality, connectivity, value chain). UK SRS S2 is the climate standard, built on the four-pillar TCFD architecture, and it carries the emissions requirements including Scopes 1, 2 and 3. They also arrive in opposite order to their numbering: UK SRS S2 is proposed to be mandatory from 1 January 2027, while UK SRS S1 follows on comply-or-explain from 1 January 2029.

TCFD yes, SECR no. Under FCA CP26/5 the TCFD-aligned Listing Rules are proposed for deletion and replacement by mandatory UK SRS S2 disclosures; the TCFD itself was disbanded in 2023 and its recommendations were absorbed into the ISSB standards that UK SRS is built on. SECR is separate. It sits in company law rather than the Listing Rules, applies to a far larger population on the 2-of-3 test (£36m turnover, £18m balance sheet, 250 employees), and continues alongside UK SRS — the government has said it will consider the interaction between the two to reduce duplication, but SECR has not been withdrawn.

Not directly — they apply through UK SRS. IFRS S1 and IFRS S2 are the ISSB's global baseline, issued in June 2023. The UK did not adopt them verbatim: it ran an endorsement assessment and published UK SRS S1 and UK SRS S2 on 25 February 2026 as the UK versions, with six UK-specific amendments to the ISSB text. So a UK company reports against UK SRS, not against IFRS S1 and S2 as issued. The two are close enough that companies already reporting on the ISSB baseline will recognise almost all of it, but the effective dates, the transitional reliefs and the SASB position are UK-specific.