UK Carbon Reporting Requirements: The 2026 Guide

There is no single "UK carbon reporting law". What businesses call UK carbon reporting requirements is really a patchwork of separate regimes: mandatory financial-year disclosures such as SECR and climate-related financial disclosure, energy-audit duties under ESOS, procurement conditions like PPN 006 and the NHS supplier rules, border measures such as CBAM, and fast-emerging standards including UK SRS. Whether any of them apply to you depends on your company's size, ownership, sector and — increasingly — who you sell to. This guide maps every requirement that is live or landing in 2026, who each one catches, and what is changing.

Key takeaways

• There is no one law. UK carbon reporting is a stack of size-, sector- and customer-driven rules, and most businesses sit in more than one at once.
• SECR is the main mandatory regime — and its thresholds did not rise when Companies Act company-size limits were uplifted in April 2025.
• Procurement is the sharpest edge for smaller firms: PPN 006 (central government, over £5m/yr) and the NHS's much wider requirement from April 2027.
• New for 2026–27: final UK SRS standards published (voluntary for now), UK CBAM starts 1 January 2027, the EU CBAM is already live, and SBTi's Net-Zero Standard V2.0 takes effect in February 2027.
• Every one of these rests on the same foundation — a GHG-Protocol-aligned carbon footprint. Get that right once and it feeds every framework you face.

Is there a single UK carbon reporting law?

No. The UK has never had one consolidated carbon-disclosure statute. Instead, obligations have accumulated over the years through company law, energy regulation, financial-services rules, procurement policy and, most recently, trade measures. Two firms of similar size can face completely different requirements — a listed manufacturer exporting to the EU has almost nothing in common, compliance-wise, with a private services business bidding for a council contract.

That is why the honest first question is never "how do I do UK carbon reporting?" but "which of these requirements actually applies to me?" The table below is the fastest way to sort that out; the sections after it explain each regime in turn.

Which carbon reporting requirements apply to your business?

Requirement	Who it applies to	Status in 2026
SECR	All quoted companies; large unquoted companies and LLPs	In force; thresholds unchanged
Climate-related financial disclosure (TCFD-aligned)	Large companies/LLPs (500+ employees) and listed issuers	In force; listing-rule limb set to move to UK SRS
ESOS (Phase 4)	Large undertakings (250+ staff, or £44m+ turnover and £38m+ balance sheet)	Compliance due 5 December 2027
PPN 006	Bidders for central government contracts over £5m/yr	In force since 24 February 2025
NHS Carbon Reduction Plans	NHS suppliers	Wider rules from 1 April 2027
UK CBAM	Importers of certain carbon-intensive goods	Starts 1 January 2027
EU CBAM	UK exporters of certain goods to the EU	Definitive regime live since 1 January 2026
UK SRS	Any entity (voluntary); listed firms proposed from 2027	Final standards published February 2026

SECR: the UK's main mandatory carbon report

Streamlined Energy and Carbon Reporting (SECR) is the closest thing the UK has to a general-purpose mandatory carbon report. It has applied to financial years beginning on or after 1 April 2019 and sits inside your annual accounts, so for most in-scope organisations it is the requirement that comes round every year without a tender or a customer request prompting it.

Who must report under SECR?

Three groups are caught, per the SECR regulations (SI 2018/1155): all UK quoted companies of any size; large unquoted companies; and large LLPs. "Large" for SECR means meeting at least two of three tests — turnover of more than £36 million, a balance sheet total of more than £18 million, or more than 250 employees.

What SECR asks you to disclose

Quoted companies report their annual global Scope 1 and Scope 2 emissions in tonnes of CO2e, underlying global energy use, at least one intensity ratio, prior-year comparatives, a UK/offshore split and the energy-efficiency actions they have taken — all in the directors' report. Large unquoted companies report their UK energy use (electricity, gas and transport fuel as a minimum), the associated Scope 1 and 2 emissions, an intensity metric, comparatives and efficiency actions; large LLPs make equivalent disclosures in a standalone energy and carbon report. Organisations that used 40,000 kWh or less in the UK over the period can omit the figures but must say they are a low energy user.

The threshold trap: SECR did not change in April 2025

This is the single most common 2026 misconception, so it is worth being blunt about. The roughly 50% uplift to Companies Act company-size thresholds for financial years beginning on or after 6 April 2025 — which moved the "large" monetary limits to more than £54m turnover and more than £27m balance sheet — did not touch SECR. The current text of Schedule 7 Part 7A still hard-codes £36m, £18m and 250 employees. A company that has just been reclassified as "medium" for its accounts can therefore still be firmly in scope of SECR. Check against the SECR figures, not your new accounts category.

Climate-related financial disclosure — and the shift to UK SRS

Layered on top of SECR is a separate, more forward-looking obligation: mandatory climate-related financial disclosure. Under the Climate-related Financial Disclosure Regulations 2022, TCFD-aligned disclosures must appear in the strategic report for financial years beginning on or after 6 April 2022. Broadly, this catches larger public-interest entities and AIM companies with more than 500 employees, plus other UK companies with more than 500 employees and turnover above £500 million, with parallel rules for LLPs. Listed companies additionally make a comply-or-explain TCFD-consistency statement under the FCA's listing rules.

That listing-rule limb is now changing. The final UK Sustainability Reporting Standards — UK SRS S1 and S2, the UK-endorsed versions of the ISSB's IFRS S1 and S2 — were published by the Department for Business and Trade on 25 February 2026. They are voluntary for any entity today, with no fixed effective date. But the FCA's consultation paper CP26/5, published on 30 January 2026, proposes replacing the TCFD-based listing rules with UK SRS-based reporting for accounting periods beginning on or after 1 January 2027, with a Policy Statement expected in autumn 2026. The government has separately signalled an ambition to consult on requiring "economically significant" companies to use UK SRS — but no such requirement exists yet, so treat anything beyond the FCA's listed-company proposal as direction of travel, not law.

A related point for groups with EU operations: after the EU's Omnibus reforms (in force from 18 March 2026), the CSRD now catches only companies with more than 1,000 employees and net turnover above €450 million — removing an estimated 80% of previously in-scope firms. A UK-headquartered group is generally only pulled into CSRD group reporting where it has substantial EU turnover and a sizeable EU subsidiary or branch, so most UK SMEs that once feared CSRD are now out of it.

ESOS: mandatory energy audits (Phase 4)

The Energy Savings Opportunity Scheme (ESOS) is not a carbon report as such — it is a mandatory energy-audit regime — but it draws on the same energy and emissions data, so it belongs in any complete picture. Phase 4 runs from 6 December 2023 to 5 December 2027, with a qualification date of 31 December 2026 and a compliance deadline of 5 December 2027.

You qualify if, on the qualification date, you are a UK "large undertaking": 250 or more employees, or turnover over £44 million together with a balance sheet total over £38 million, per the ESOS guidance on GOV.UK. Note these are different figures from SECR — it is entirely possible to be caught by one and not the other. Compliance means measuring total energy consumption across buildings, transport and processes, auditing the areas of significant use (or covering them through ISO 50001), appointing an approved lead assessor, obtaining board-level sign-off and notifying the Environment Agency. Phase 4 is expected to remove Display Energy Certificates and Green Deal Assessments as compliance routes and to add progress reporting against action-plan commitments, though those changes remain subject to parliamentary time.

Procurement requirements: PPN 006 and the NHS

For many businesses — including SMEs that fall well under the SECR and ESOS size tests — the requirement that actually bites first arrives through a tender. PPN 006 (the successor to PPN 06/21 for procurements commenced on or after 24 February 2025 under the Procurement Act 2023) requires bidders for central government contracts worth more than £5 million a year, including VAT, to publish a Carbon Reduction Plan. That plan must commit to net zero by 2050, report Scope 1, Scope 2 and five defined Scope 3 categories, and be signed off by a director and published on the bidder's UK website. Because a compliant plan is a condition of participation, a business without one is simply excluded from the competition. We explain the full requirement, category by category, in What is PPN 006? Carbon Reduction Plans explained.

The bigger 2026 development is on the NHS side, and it is frequently confused with a change to PPN 006 — it is not. Under NHS England guidance published on 9 June 2026, from 1 April 2027 NHS procurements worth £5 million a year or more, plus all new frameworks and dynamic markets regardless of value, will require a Carbon Reduction Plan covering global Scope 1, Scope 2 and all relevant Scope 3 emissions across the GHG Protocol's fifteen categories — far beyond the five categories PPN 006 asks for. If you sell to the NHS, that is a materially larger measurement job, and 1 April 2027 is close enough to start on now.

Carbon at the border: UK and EU CBAM

Carbon Border Adjustment Mechanisms are the newest layer, and they work in both directions. The UK CBAM starts on 1 January 2027, legislated through the Finance Act 2026. It applies to imports of aluminium, cement, fertiliser, hydrogen and iron and steel, with a minimum registration threshold of £50,000 of CBAM goods over a rolling 12 months. Importers pay a levy on the embedded direct emissions of those goods, priced off UK ETS values, and can use verified actual emissions data or government default values. The first accounting period is the whole of 2027, with payment due by the end of May 2028; indirect emissions are excluded until at least 2029.

If you export rather than import, the EU's scheme is the live concern. The EU CBAM definitive regime began on 1 January 2026, and the EU has confirmed there is no UK exemption until a UK–EU emissions-trading link is in force. In practice that means UK exporters of CBAM goods are already being asked by their EU customers for verified embedded-emissions data, so that those customers can buy CBAM certificates and file their first annual declaration by 30 September 2027. Even below the mandatory thresholds, expect the data request to arrive through your customer long before any law reaches you directly.

Science-based targets: voluntary, but increasingly expected

None of the above requires you to set a science-based target — but customers, investors and tender scorecards increasingly do. The Science Based Targets initiative published the final Corporate Net-Zero Standard V2.0 on 11 June 2026, effective from 1 February 2027 (companies can still submit under V1.3.1 until 31 January 2028). V2.0 introduces company categories — larger firms in higher-income countries face the full obligations including mandatory assurance and transition plans, while SMEs get proportionate requirements — along with separate Scope 1 and Scope 2 targets, a tighter Scope 3 approach and a clearer framework for carbon removals. It is voluntary, but if a buyer asks for validated targets, this is now the standard they mean.

What every UK carbon reporting requirement has in common

Read the sections above and one thing becomes obvious: however different the frameworks look, they all rest on the same foundation. Every one of them — SECR, climate-related disclosure, PPN 006, the NHS rules, CBAM, UK SRS and SBTi — is built on a greenhouse-gas inventory measured to the GHG Protocol, reported in tonnes of CO2e across the seven Kyoto gases. Get that footprint right once, with clean data and a defensible boundary, and it feeds every requirement you face rather than being rebuilt from scratch each time a tender or a regulator asks.

To be clear about what we do and don't do: Carbon Managers does not file your SECR return, write your Carbon Reduction Plan, run your ESOS audit or validate your SBTi targets — those are jobs for your accountants, lead assessors and the relevant bodies. What we do, and have done since 2007, is build the GHG-Protocol-aligned carbon footprint that all of those requirements depend on. If you know one of these requirements is coming — a tender on the horizon, a customer asking for data, a reporting threshold you have crossed — the practical first step is almost always the same: measure your emissions properly, once, in a form you can reuse. That is the work that makes every framework above manageable rather than a fire drill.