The UK sustainability regulation timeline: every regime on one calendar

Three corporate regimes bind today, and none of them is a sustainability reporting standard.

SECR, in force since 1 April 2019, puts energy and carbon reporting into the directors’ report under Schedule 7 of SI 2008/410.

The Companies Act climate disclosures in section 414CB apply to financial years beginning on or after 6 April 2022, for companies with more than 500 employees that are traded, banking, insurance or AIM companies or have turnover above £500 million.

ESOS Phase 4 has run since 6 December 2023 and is judged on 31 December 2026; the details are on the ESOS hub and ESOS Phase 4 thresholds.

For financial firms, the FCA’s SDR rules have applied in stages since 31 May 2024, and the PRA’s SS5/25 has set its climate-risk expectations since 3 December 2025 — expectations, not a reporting duty.

The government decided on 15 July 2025 not to take the UK Green Taxonomy forward, and the transition plan consultation has produced no outcome.

The wider picture is on the UK sustainability regulation landscape, nature on nature-related disclosures, and the transition-plan position on UK transition plan regulation.

From 1 January 2027 listed companies in five categories report against UK SRS on a comply-or-explain basis (PS26/19), with the first reports published in 2028.

The UK carbon border adjustment mechanism starts the same day under Finance Act 2026 Part 5; it is a tax, not a reporting standard.

The EU’s revised ESRS apply to financial years beginning on or after 1 January 2027 (DR (EU) 2026/1563), reaching a UK group through its EU undertakings.

ESOS Phase 4 ends with notification of compliance by 5 December 2027 (Environment Agency); how it differs from Phase 3 is on ESOS Phase 3 vs Phase 4.

Your own UK SRS first period is on the UK SRS deadline.

A listed group can sit inside four of these regimes at once, each with its own threshold, regulator and date.

The instruments do not share tests: SECR’s is two of three limits, ESOS’s is either-or, and the Companies Act duty needs employees and turnover or company type together.

No regulator publishes how long a sustainability report takes to prepare; the only government measurement is for SECR, where the 2026 evaluation found 94 hours of internal staff time a year.

The SECR post-implementation review recommends keeping the regime with amendments, and the Regulatory Policy Committee rated it fit for purpose on 15 May 2026.

The government’s wider framing of green finance is its green finance strategy, updated in 2023; the standards themselves remain voluntary outside the listing rules.

What the standards ask for is on what is UK SRS, and preparing for them on UK SRS compliance.