The UK has no single law on carbon offset claims. Instead, consumer protection law, the CMA’s guidance on green claims, the advertising codes and new reporting standards each cover part of the picture. Together they set a clear expectation: say plainly what you cut and what you offset, and be able to prove it. This page sets out each part. It is part of our claims and rules section.
The UK rules at a glance
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| Rule | Who sets it | What it covers |
|---|---|---|
| Green Claims Code (Sept 2021) | CMA | How consumer law applies to environmental claims |
| DMCC Act 2024 (from Apr 2025) | Parliament; enforced by the CMA | Unfair commercial practices; direct CMA fines |
| Advertising guidance (Feb 2023) | ASA and CAP | Carbon neutral and net zero claims in ads |
| UK SRS S1 and S2 (Feb 2026) | UK government | Company disclosures, including planned use of carbon credits |
As of Oct 2026 · Source: [1] Green claims code: environmental claims on goods and services
Dates come from the CMASource 1Source 2, the ASASource 5 and the UK SRS publicationSource 7.
What the Green Claims Code says about offsetting
The Competition and Markets Authority (CMA) published its Green Claims Code on 20 September 2021. It sets out six principles: claims must be truthful and accurate, clear and unambiguous, must not omit or hide important information, must make fair and meaningful comparisons, must consider the full life cycle of the product or service, and must be substantiatedSource 1.
On carbon claims, the Code says businesses should use the correct terminology and include accurate information about whether, and how far, they are reducing their own emissions or offsetting them. Where they offset, they should give information about the scheme they use, which should be based on recognised standards and capable of objective verificationSource 1.
In January 2026 the CMA added an explainer on supply chains. It says the guidance is for all businesses in the chain, including retailers, brands, manufacturers and suppliersSource 4. Traders that don’t sell to consumers directly must still make sure claims they pass to retailers are truthful and accurateSource 2.
How the CMA enforces it now
The Digital Markets, Competition and Consumers Act 2024 (DMCC Act) replaced the earlier unfair trading rules for practices from 6 April 2025Source 2. Under it, the CMA can decide whether consumer law has been broken, give directions, order redress for consumers and issue fines without going to courtSource 4.
A penalty can be up to 10% of a business’s global turnover or £300,000, whichever is greaterSource 3. When deciding whether to act, the CMA takes account of whether published guidance such as the Green Claims Code already made the expectations clearSource 4. An unwitting breach is still a breach of the law, though genuine attempts to comply can count as a mitigating factorSource 4.
What the ASA expects in adverts
On 10 February 2023 the ASA’s code-writing committees, CAP and BCAP, updated their environmental guidance to cover carbon neutral and net zero claimsSource 5. The update followed consumer research which found that people tended to read carbon neutral claims as meaning emissions had actually fallen, and could feel misled when offsetting was revealedSource 5.
ASA and CAP guidance on carbon claims
- Avoid unqualified carbon neutral, net zero or similar claims; explain the basis for them.
- Say accurately whether, and how far, you are reducing emissions or relying on offsetting.
- Base claims about future goals on a verifiable strategy to deliver them.
- Where claims rest on offsetting, meet the usual evidence standards and give information about the offsetting scheme.
- Put qualifying information close to the main claim, where consumers can see it.
The ASA said unqualified claims are likely to breach existing rulesSource 5.
Reporting: UK SRS and carbon credits
The UK government published UK Sustainability Reporting Standards S1 and S2 in February 2026, based on the ISSB’s IFRS S1 and S2. They are available for voluntary use, and the government and the Financial Conduct Authority (FCA) will consider whether to require certain UK entities to report against themSource 6. When the government page was last updated in February 2026, the FCA was consulting on related changes to the UK Listing Rules until 20 March 2026Source 6.
UK SRS S2 has a specific rule on credits. A company with a net greenhouse gas emissions target must disclose how far reaching that target relies on carbon credits, which third-party schemes will verify or certify them, whether they are nature-based or technological, whether they are reductions or removals, and anything else needed to judge their credibility, such as assumptions about permanenceSource 7. A company with a net target must also disclose a gross target, and the net target can’t obscure itSource 7.
Is there a UK ban like the EU’s?
Not in the sources above. The EU’s consumer law bans offset-based claims that a product has a neutral, reduced or positive climate impact from 27 September 2026; see our page on the EU green-claims ban. UK guidance instead requires such claims to be accurate, qualified and evidencedSource 1Source 5. If you sell in both markets, the EU rule is the stricter one for product claims.
A practical checklist for UK businesses
- Separate reductions from offsets in every claim, with figures for eachSource 1.
- Name the scheme: the standard, project and registry record for credits you retiredSource 1.
- Qualify the claim next to it, not in a footnoteSource 5.
- Back future targets with a plan you can showSource 5.
- Keep the evidence, because the CMA can now act directlySource 4.
For the wider debate on the phrase, see carbon neutral claims and net zero vs carbon neutral. For buying credits in the UK, read our United Kingdom guide.