Carbon reporting requirements UK: every regime, mapped
There is no single carbon reporting rule in the UK — there is a stack of separate regimes, each with its own scope test, output and deadline.
This page maps them: SECR, UK SRS S2, ESOS, the TCFD-aligned Listing Rules, the UK Emissions Trading Scheme, and the voluntary frameworks (CDP and science-based targets).
For each, who it applies to, what it requires, and a one-line read on whether it applies to you.
One topic, several separate rulebooks
“Carbon reporting” is not one obligation in the UK.
It is a set of distinct regimes, run by different bodies, with different qualifying tests and different purposes.
Some are mandatory disclosures placed in your annual report.
One is a four-yearly energy audit.
One is a cap-and-trade compliance market.
And two of the best-known frameworks — CDP and science-based targets — are entirely voluntary.
The fastest way to work out your obligations is to read across the regimes by who they apply to, rather than studying each in isolation.
The table below is the routing map; the sections beneath it explain each regime and link to deeper analysis.
| Regime | Status | Who it applies to | Which applies to me |
|---|---|---|---|
| SECR | Mandatory | Quoted companies; large unquoted companies and LLPs (two of three: £36m turnover, £18m balance sheet, 250 staff)[1] | You are listed, or you are large by the Companies Act test |
| UK SRS S2 (climate) | Proposed mandatory | In-scope listed companies under the FCA proposal, for periods beginning on/after 1 January 2027[5] | You are a primary-listed company in FCA scope |
| TCFD-aligned Listing Rules | Current (being replaced) | Premium-listed and certain large companies, until replaced by UK SRS S2[5] | You already report TCFD under the Listing Rules today |
| ESOS | Mandatory | Large undertakings (over £44m turnover and £38m balance sheet, or 250-plus UK employees)[3] | You are a large undertaking by the ESOS test |
| UK ETS | Mandatory | Combustion sites above 20MW rated thermal input, energy-intensive industry and in-scope aircraft operators[6] | You run a large combustion/industrial site or airline |
| CDP | Voluntary | Any company; typically completed at an investor’s or customer’s request[7] | An investor or major buyer has asked you to disclose |
| Science-based targets | Voluntary | Any company setting validated 1.5°C-aligned reduction targets[7] | You want a credible, externally validated net-zero target |
SECR: annual energy and carbon in the Directors’ Report
Streamlined Energy and Carbon Reporting is the baseline UK disclosure obligation. It was introduced by the 2018 SECR Regulations and took effect for accounting periods from 1 April 2019[2].
It applies to quoted companies of any size, and to large unquoted companies and LLPs. “Large” means exceeding two of three thresholds: turnover over £36m, balance sheet total over £18m, or more than 250 employees[1].
In-scope entities report their UK energy use, Scope 1 and Scope 2 greenhouse gas emissions, at least one intensity ratio, and the energy-efficiency action taken. The disclosure sits in the Directors’ Report and is filed with the annual report[2].
The methodology follows the GHG Protocol Corporate Standard and the Government’s environmental reporting guidelines[7]. For the full scope test and exemptions, see our SECR requirements guide.
UK SRS S2: mandatory climate reporting for listed companies
The UK Sustainability Reporting Standards are the UK’s adoption of the ISSB’s IFRS S1 and S2.
UK SRS S2 covers climate-related disclosures: governance, strategy, risk management, and metrics and targets including Scope 1, 2 and 3 emissions.
In CP26/5, the FCA proposed replacing the existing TCFD-aligned Listing Rules with rules requiring in-scope listed companies to report against UK SRS S2 for accounting periods beginning on or after 1 January 2027[5].
That consultation closed on 20 March 2026; the FCA is reviewing responses and expects a Policy Statement in autumn 2026, so the mandatory dates remain proposals until then[5].
UK SRS is a judgement-based, materiality-driven standard — distinct from SECR’s rule-based disclosure — and the two regimes run in parallel. See our UK SRS requirements guide for the detail, and TCFD reporting for the rules it replaces.
ESOS: the four-yearly energy audit
The Energy Savings Opportunity Scheme is a mandatory energy assessment, not a public emissions disclosure. It is administered by the Environment Agency under the 2014 ESOS Regulations and runs in four-year phases[3].
It applies to large undertakings — those with more than £44m turnover and a balance sheet total over £38m, or 250 or more UK employees. If any UK group entity qualifies, the whole UK group is in scope[3].
Qualifying organisations must audit their energy use, identify cost-effective savings, and notify the regulator. The Phase 4 notification deadline is 5 December 2027[4].
ESOS and SECR are frequently confused but use different tests and produce different outputs. Our ESOS Phase 4 guide covers the audit obligations, and ESOS vs SECR sets the two regimes side by side.
UK ETS: the cap-and-trade obligation
The UK Emissions Trading Scheme is a cap-and-trade market rather than a reporting framework, but for heavy-emitting sites it is the most direct carbon obligation of all.
It applies to regulated activities that produce greenhouse gas emissions, including combustion of fuels at sites where combustion units have a total rated thermal input exceeding 20MW, and to in-scope aircraft operators[6].
The scheme covers the UK’s power sector, energy-intensive industry and aviation. Participants must monitor, report and surrender allowances for their emissions each scheme year[6].
Simplified provisions exist for hospitals and small emitters and for ultra-small emitters, reducing the administrative burden on lower-emitting sites[6].
CDP and science-based targets: voluntary, but expected
Two of the most visible carbon frameworks are not required by UK law at all.
They are voluntary, but in many supply chains and investment processes they have become de facto expectations.
CDP runs an annual environmental disclosure questionnaire. Companies usually complete it because an investor or a major customer asks them to, and a published score becomes a procurement and investment signal.
Science-based targets are emissions-reduction goals validated against a 1.5°C pathway by the Science Based Targets initiative. They give a net-zero claim external credibility.
Both rely on robust Scope 1, 2 and 3 data built on the GHG Protocol[7]. See our CDP reporting guide, science-based targets and Scope 3 emissions reporting.
Carbon reporting requirements: frequently asked questions
Which carbon reporting requirements apply to my company?
It depends on your size, legal form and whether you are listed. Large companies and LLPs meeting two of three thresholds — turnover over £36m, balance sheet over £18m, or more than 250 employees — must report energy and carbon under SECR. Large undertakings meeting the ESOS test (over £44m turnover and over £38m balance sheet, or 250-plus UK employees) must complete an ESOS energy audit every four years. Premium-listed and certain large companies report under the existing TCFD-aligned Listing Rules, which the FCA proposes to replace with mandatory UK SRS S2 climate reporting for accounting periods beginning on or after 1 January 2027. Operators of large combustion and industrial sites and most aircraft operators are caught by the UK Emissions Trading Scheme. CDP and science-based targets are voluntary but increasingly requested by investors and customers.
What is the difference between SECR and ESOS?
They are separate regimes with different tests and outputs. SECR is an annual disclosure of energy use and greenhouse gas emissions placed in the Directors’ Report, governed by the Companies Act 2006 and the 2018 SECR Regulations. ESOS is a four-yearly energy audit obligation administered by the Environment Agency under the 2014 ESOS Regulations; it identifies cost-effective energy savings but is not a public emissions disclosure. A company can be in scope of one, both or neither because the qualifying thresholds differ — SECR uses a two-of-three test in pounds, while ESOS uses a turnover-and-balance-sheet test or a 250-employee test.
Is SECR the same as UK SRS climate reporting?
No. SECR and UK SRS are separate obligations that the Department for Business and Trade has confirmed will continue in parallel. SECR is a rule-based disclosure of energy and emissions in the Directors’ Report. UK SRS S2 is a judgement-based, materiality-driven climate-risk standard that sits in the Strategic Report and requires governance, strategy, risk-management and metrics disclosures, including Scope 3 emissions. Companies caught by both will report under each regime, with limited cross-references rather than a merged report.
What is the UK Emissions Trading Scheme (UK ETS) and who is in it?
The UK ETS is a cap-and-trade scheme covering the power sector, energy-intensive industry and aviation. It applies to combustion of fuels at sites where combustion units have a total rated thermal input exceeding 20MW, and to in-scope aircraft operators. Participants must monitor, report and surrender allowances for their emissions each scheme year. It is an operational compliance market rather than a corporate disclosure framework, but it is the most direct carbon obligation for heavy-emitting installations and airlines.
Are CDP and science-based targets mandatory in the UK?
No. Both are voluntary. CDP runs an annual environmental disclosure questionnaire used by investors and large buyers, and companies often complete it because a customer or shareholder asks them to. The Science Based Targets initiative validates corporate emissions-reduction targets against a 1.5°C pathway. Neither is required by UK law, but both have become de facto expectations in many supply chains and investment processes.
- Companies Act 2006, sections 414CB and 465–466 (size thresholds and energy/carbon reporting) — legislation.gov.uk · SECR large-company test: two of three — turnover £36m, balance sheet £18m, 250 employees
- The Companies (Directors’ Report) and Limited Liability Partnerships (Energy and Carbon Report) Regulations 2018 (SI 2018/1155) — legislation.gov.uk · SECR Regulations, effective 1 April 2019
- The Energy Savings Opportunity Scheme Regulations 2014 (SI 2014/1643), Regulation 5 — legislation.gov.uk · ESOS qualification thresholds and four-year compliance cycle
- Comply with the Energy Savings Opportunity Scheme (ESOS) — GOV.UK / Environment Agency · ESOS Phase 4 notification deadline 5 December 2027
- CP26/5: Aligning listed issuers’ sustainability disclosures with international standards — Financial Conduct Authority · Proposed mandatory UK SRS S2 from 1 January 2027; closed 20 March 2026
- Participating in the UK ETS — GOV.UK / DESNZ & Environment Agency · UK ETS scope: 20MW total rated thermal input; power, industry and aviation
- GHG Protocol — Corporate Standard and Corporate Value Chain (Scope 3) Standard — Greenhouse Gas Protocol · Methodological basis for Scope 1, 2 and 3 emissions accounting