Regulatory Intelligence

ESG & Climate Regulatory Insights

Independent, practitioner-focused guidance on UK SRS, SECR, ISSB, CSRD, CBAM, TNFD, Net Zero, and assurance readiness — helping UK companies navigate mandatory sustainability disclosure.

Educational and advisory content only. RSustain does not provide statutory assurance or verification services.

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What This Page Covers

This knowledge hub provides independent analysis of the regulatory developments, reporting frameworks, and practical implementation methods shaping ESG disclosure in the United Kingdom. Topics include UK Sustainability Reporting Standards (UK SRS), SECR, ISSB/IFRS S1 and S2, CSRD and ESRS (for UK companies with EU operations), UK CBAM, UK ETS, TNFD, SBTi V2.0, GHG Protocol, Scope 1–3 carbon accounting, transition planning, and assurance readiness.

All content is written by the RSustain UK Advisory Team. We cover UK regulation with international context, helping organisations prepare for disclosure, audit scrutiny, and investor expectations.

Latest Insights

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Regulatory Knowledge Base

Concise, practitioner-focused explainers on the frameworks and regulations shaping ESG disclosure in the UK and internationally.

CSRD

Corporate Sustainability Reporting Directive — EU disclosure requirements under ESRS, affecting UK companies with EU operations.

UK SDR

UK Sustainability Disclosure Requirements — FCA rules for investment labels, anti-greenwashing, and entity-level disclosures.

ISSB / IFRS S1 & S2

International sustainability disclosure standards forming the basis of UK SRS. Mandatory for UK-listed companies from January 2027.

Double Materiality

The CSRD assessment methodology examining both financial impacts and environmental/social impacts of business activities.

Scope 3 Emissions

Value chain emissions — the most complex GHG category, now required under UK SRS S2 on a comply-or-explain basis.

SECR

Streamlined Energy and Carbon Reporting — UK mandatory carbon and energy disclosure for qualifying companies.

ESOS

Energy Savings Opportunity Scheme — mandatory energy audit obligations for large UK undertakings. Phase 4 qualifies December 2026.

UK ESG Regulatory Timeline

Key upcoming dates for UK sustainability reporting and carbon compliance.

January 2027
UK SRS Mandatory Reporting Begins
~515 UK-listed companies commence first mandatory UK SRS S1/S2 reporting period. Scope 3 on comply-or-explain.
January 2027
UK CBAM Takes Effect
Carbon costs on imports of aluminium, cement, fertiliser, hydrogen, and iron/steel. Registration and reporting obligations for importers.
December 2027
ESOS Phase 4 Compliance Deadline
Large UK undertakings must complete enhanced energy audits with action plans and progress reports.
2028
UK ETS Waste Incineration Mandatory
Energy-from-waste operators must surrender UK ETS allowances for verified emissions. MRV-only period runs from January 2026.
2028
First UK SRS Reports Published
Listed companies publish first annual reports containing mandatory UK SRS S1 and S2 disclosures.

Frequently Asked Questions

What is CSRD and does it apply to UK companies?+
The Corporate Sustainability Reporting Directive requires organisations operating in the EU to disclose standardised sustainability information aligned with ESRS. UK companies are in scope if they have EU-listed subsidiaries, or generate EUR 150m+ net turnover in the EU with an EU subsidiary or branch exceeding certain thresholds. The EU Omnibus “Stop-the-Clock” Directive (April 2025) has delayed Wave 2 by two years, but Wave 1 companies (largest EU-listed) are already reporting.
What are UK SRS S1 and S2?+
UK Sustainability Reporting Standards S1 (General Requirements) and S2 (Climate-related Disclosures) are the UK’s endorsed versions of ISSB IFRS S1 and S2. Published in final form in February 2026, they become mandatory for approximately 515 UK-listed companies for accounting periods beginning on or after 1 January 2027. UK SRS S2 requires disclosure of Scope 1, 2, and 3 emissions, climate risks and opportunities, transition plans, and governance arrangements. Scope 3 is on a comply-or-explain basis with one year of transitional relief.
Does RSustain provide assurance services?+
No. RSustain provides advisory and system design services only. We help organisations build assurance-ready ESG data systems, governance structures, and reporting processes. Statutory assurance or verification must be obtained from an independent assurance provider (e.g., a registered auditor or accredited verifier).
What is the UK CBAM and when does it start?+
The UK Carbon Border Adjustment Mechanism takes effect from 1 January 2027. It applies to imports of aluminium, cement, fertiliser, hydrogen, and iron/steel, imposing carbon costs reflecting embedded emissions. Importers must register, report emissions, and purchase CBAM certificates. Secondary legislation was laid before Parliament in September 2026.
What is assurance-ready ESG reporting?+
Assurance-ready reporting means ESG disclosures supported by documented controls, calculation notes, evidence trails, and governance structures that can withstand independent audit scrutiny. The five pillars are: evidence management, internal controls, calculation discipline, governance structures, and disclosure architecture. Companies that design for assurance from the outset avoid costly retrofitting.
How do ISSB standards relate to CSRD?+
ISSB (via IFRS S1/S2, adopted in the UK as UK SRS) focuses on investor-grade financial materiality disclosures. CSRD (via ESRS) requires double materiality — covering both financial impacts and environmental/social impacts. Companies operating across both jurisdictions must understand and implement both frameworks, though there is significant overlap. EFRAG and ISSB have published interoperability guidance to help companies map between the two.
What is the difference between SECR and UK SRS?+
SECR (Streamlined Energy and Carbon Reporting) requires qualifying UK companies to disclose energy use, Scope 1 and 2 emissions, and an intensity ratio in their annual reports. UK SRS is significantly broader — requiring climate risk and opportunity analysis, Scope 3 emissions, transition plans, governance disclosures, and alignment with TPT. UK SRS will eventually supersede TCFD-aligned reporting; the government has proposed consolidating overlapping requirements.
What is SBTi V2.0 and how does it affect UK companies?+
The Science Based Targets initiative published its revised Corporate Net-Zero Standard V2.0 in June 2026. Key changes include relevance-based Scope 3 target boundaries (5% category threshold), flexible alignment-based targets, and Ongoing Emissions Responsibility replacing BVCM. Companies with existing validated SBTi targets must plan revalidation under V2.0 within the transition window.

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