Quick Answer — IFRS S1 & S2 UK Status
What is the ISSB?
The International Sustainability Standards Board (ISSB) was established by the IFRS Foundation at COP26 in November 2021.
Mandate: Create a global baseline of sustainability disclosure standards that provide investors with information about companies' sustainability-related risks and opportunities.
Built on existing frameworks: IFRS S1 and S2 consolidate and build upon the Task Force on Climate-related Financial Disclosures (TCFD), Sustainability Accounting Standards Board (SASB), and Integrated Reporting frameworks (IFRS Foundation).
Global coordination: Designed to work alongside jurisdiction-specific requirements like ESRS in the EU and UK SRS in the UK.
IFRS S1 Explained
For the full standard, see our dedicated IFRS S1 guide.
Full title: General Requirements for Disclosure of Sustainability-related Financial Information
Purpose: Cross-cutting framework that establishes the foundation for all sustainability-related disclosures.
Sets out general requirements that apply alongside topic-specific standards (like IFRS S2 for climate).
Core requirements:
- Materiality assessed by reference to cash flows, access to finance or cost of capital, judged by influence on the decisions of primary users (investors, lenders, creditors)
- Four-pillar disclosure architecture: governance, strategy, risk management, metrics and targets
- Reporting boundary aligned with financial statements
- Annual reporting frequency with interim updates where material changes occur
Industry guidance: Permits reference to SASB Standards and other authoritative sources for industry-specific metrics (IFRS S1).
IFRS S2 Explained
For the full standard, including scenario analysis and Scope 1-3 detail, see our dedicated IFRS S2 guide.
Full title: Climate-related Disclosures
Purpose: Requires disclosure of climate-related risks and opportunities that could reasonably be expected to affect an entity's cash flows, access to finance, or cost of capital.
Built on TCFD: Adopts the TCFD four-pillar framework but makes scenario analysis mandatory (not just recommended) and requires Scope 1, 2, and 3 emissions disclosure (IFRS S2).
Key requirements:
- Governance: Climate oversight by board and management
- Strategy: Climate risks and opportunities assessment, scenario analysis
- Risk management: Climate risk identification, assessment, and management processes
- Metrics and targets: GHG emissions (Scopes 1, 2, 3), climate-related targets, and financial impacts
Scenario analysis: Required, using an approach commensurate with the entity's circumstances.
No particular scenario is prescribed — paragraph 22(b)(i) requires the entity to disclose, among the inputs to its analysis, whether the scenarios used align with the latest international agreement on climate change (IFRS S2).
Is IFRS S1 and S2 Mandatory in the UK?
Direct answer: NO — IFRS S1 and S2 are not directly mandatory in the UK.
UK adoption route: The UK government has adopted IFRS S1 and S2 as the basis for UK SRS S1 and UK SRS S2, published by DBT on 25 February 2026.
UK mandatory scope: UK SRS S2 is proposed mandatory for 515 companies in UKLR categories 6, 16 and 22 from accounting periods beginning 1 January 2027, subject to FCA Policy Statement (expected autumn 2026).
UKLR 14 and 15 (89 companies) are within CP26/5's scope but would instead make a signposting statement about the overseas standards they follow, not report under UK SRS.
Key difference: UK SRS = IFRS S1 and S2 with UK-specific amendments set out in Annex A of the government response (see below).
IFRS S1 and S2 in the UK — 2026 update
On 25 February 2026, the Department for Business and Trade published UK SRS S1 and UK SRS S2 — the UK-endorsed versions of IFRS S1 and S2, based on the ISSB standards with limited UK amendments.
The FCA followed with CP26/5 on 30 January 2026, proposing mandatory UK SRS S2 reporting for 515 of the ~600 listed companies affected (UKLR categories 6, 16 and 22) for accounting periods beginning on or after 1 January 2027, with the remaining 89 companies (UKLR 14 and 15) instead making a signposting statement about the overseas standards they follow.
Under the proposals, Scope 3 emissions are comply-or-explain in the first year, and the UK SRS S1 general requirements apply on a comply-or-explain basis from 2029 (FCA CP26/5).
The consultation closed on 20 March 2026, with the FCA policy statement expected in autumn 2026.
For the differences in detail, see UK SRS vs IFRS S1/S2; for the UK regime as a whole, start with What is UK SRS?
UK Amendments (Difference Between IFRS and UK SRS)
UK SRS adopts IFRS S1 and S2 as the baseline.
The UK government consulted on six proposed amendments in June 2025; the final Standards differ from IFRS S1 and S2 as set out in Annex A of the government's consultation response, which carries no count:
| Amendment | IFRS S1/S2 | UK SRS S1/S2 |
|---|---|---|
| S1 first-year relief | Available | Removed |
| Climate-first relief (¶E3) | 1-year transition | Retained, no time limit in the Standard |
| SASB requirements | Shall refer to | May refer to |
| Financed emissions (¶B59A) | Not specified | Added disclosure duty when impracticable |
| Effective dates | Global dates | UK effective dates removed |
These amendments tailor IFRS S1 and S2 to UK legal and regulatory context while maintaining international consistency (DBT).
Our UK SRS vs IFRS S1/S2 comparison works through each amendment in detail.
Global Adoption Status
As of March 2025, 15 jurisdictions have adopted IFRS S1/S2 on voluntary or mandatory basis, with 21 others planning adoption (S&P Global).
Jurisdictions adopting represent over 50% of global GDP.
The FCA's CP26/5 puts the wider figure at approximately 40 jurisdictions that have adopted or intend to adopt ISSB standards.
Key jurisdictions
UK: Via UK SRS S1/S2 with amendments, proposed mandatory 2027 (DBT)
Australia: AASB S1 and S2 adopted with Australian modifications.
Phased mandate: Group 1 entities from FY2024-25, Group 2 from FY2026-27, Group 3 from FY2027-28 (S&P Global adoption tracker).
Japan: SSBJ issued three sustainability standards on 5 March 2025, aligned with ISSB standards but split S1 into separate General and Application standards (S&P Global).
Singapore: SGX mandated ISSB-aligned climate reporting for all listed companies.
MAS incorporated ISSB expectations for financial institutions.
Other adopters: Hong Kong, Malaysia, Brazil, Nigeria, and California have announced alignment or consultations (S&P Global).
IFRS S1/S2 vs ESRS vs UK SRS
| Framework | Authority | Scope | Materiality | Status |
|---|---|---|---|---|
| IFRS S1/S2 | ISSB / IFRS Foundation | Global baseline | Single (financial) | Global standard |
| UK SRS S1/S2 | DBT / FCA | UK listed companies | Single (financial) | UK adoption with amendments (Annex A) |
| ESRS (CSRD) | European Commission | EU companies >1,000 employees | Double (financial + impact) | EU mandatory from 2024 |
| TCFD | FSB | G20 voluntary | Financial materiality | Being superseded by IFRS S2 |
This shows IFRS S1/S2 as the emerging global baseline, with UK and EU adopting jurisdiction-specific versions while maintaining core alignment.
What are IFRS S1 and S2?
IFRS S1 (General Requirements) and S2 (Climate-related Disclosures) are global sustainability disclosure standards issued by the ISSB on 26 June 2023.
S1 provides the foundation framework, while S2 covers climate-specific requirements including scenario analysis and Scope 1, 2, 3 emissions.
Is IFRS S1 and S2 proposed mandatory in the UK?
Not directly.
The UK has adopted IFRS S1 and S2 as UK SRS S1 and S2 with a set of UK-specific amendments (DBT publishes no count of them).
UK SRS S2 is proposed mandatory for 515 of the ~600 listed companies affected — UKLR categories 6, 16 and 22 — from 1 January 2027 under FCA CP26/5; the remaining 89 companies (UKLR 14 and 15) would instead make a signposting statement about the overseas standards they follow.
Who issues IFRS S1 and S2?
The International Sustainability Standards Board (ISSB), established by the IFRS Foundation at COP26 in November 2021.
The ISSB creates global sustainability disclosure standards to provide investors with consistent information.
What is the difference between IFRS and UK SRS?
UK SRS adopts IFRS S1 and S2 as the baseline.
The government consulted on six proposed amendments in June 2025; the final Standards remove S1 first-year relief, retain climate-first relief with no time limit, soften SASB requirements from "shall" to "may", add a disclosure duty for financed emissions when impracticable (¶B59A), and remove global effective dates rather than replacing them.
GICS classification was dropped from IFRS S1/S2 itself by the ISSB in December 2025, not by a UK amendment.
Are IFRS S1 and S2 proposed mandatory anywhere?
Yes, 15+ jurisdictions have adopted them as mandatory or voluntary standards as of March 2025.
Australia uses AASB S1/S2 with phased mandates from 2024.
Singapore mandated ISSB-aligned reporting for all listed companies.
The UK proposes mandatory reporting from 2027 via UK SRS.
What is the 2026 UK update for IFRS S1 and S2?
Two things happened in early 2026: DBT published UK SRS S1 and S2 (the UK-endorsed versions of IFRS S1 and S2) on 25 February 2026, and the FCA published CP26/5 on 30 January 2026 proposing mandatory UK SRS S2 reporting for 515 of the ~600 listed companies affected, from accounting periods beginning 1 January 2027.
The FCA policy statement is expected in autumn 2026.
How does IFRS S2 compare to TCFD?
IFRS S2 builds on TCFD's four-pillar framework but makes scenario analysis mandatory (not recommended), requires Scope 3 emissions disclosure, and provides more detailed requirements.
TCFD is being superseded by IFRS S2 and jurisdiction-specific adoptions like UK SRS S2.
