The word "sustainable" is doing a lot of quiet work on British packaging right now, and a lot of it is not the work the word thinks it's doing. Walk into any high street and you'll see it stamped on coffee cups, printed on tote bags, painted onto the side of vans. Most of it is meant well. Some of it is meant carefully. A surprising amount of it, if it ended up in front of the Competition and Markets Authority or the Advertising Standards Authority, would come apart under a fairly gentle push. That is what the Green Claims Code exists to prevent. It is the UK's rulebook for what a business can and cannot say about its environmental credentials, and in 2026 it has more force behind it than at any point since it was published. If you are a marketing lead, a sustainability manager, a founder, or the person unlucky enough to have "and comms" in your job title, this is the version of the Code you actually need. Not the summary. The working version. The one that gets to the sentence you were about to publish and shows you what to do with it.
What the Green Claims Code actually is
The Green Claims Code is the CMA's guidance for businesses making environmental claims to UK consumers. It was published in September 2021 and sets out six principles: claims must be truthful and accurate, clear and unambiguous, not omit or hide important information, only compare products fairly, consider the full life cycle, and be substantiated (CMA, Green Claims Code).
Those six principles are the whole spine. Every ruling, every investigation, every enforcement letter you'll read about traces back to one of them. The Code is aimed at consumer-facing communication, but in practice it now shapes tender responses, B2B websites, LinkedIn copy, packaging, and the small print at the bottom of an invoice. If your claim can be read by someone who might make a purchase decision, treat it as in scope.
The Green Claims Code is not a threat to businesses doing this work carefully. It is a threat to businesses doing it carelessly.
What changed in 2026 that raises the stakes
The Code itself hasn't rewritten. What has changed is the enforcement architecture around it. In April 2025, the consumer protection provisions of the Digital Markets, Competition and Consumers Act 2024 came into force (The Digital Markets, Competition and Consumers Act 2024 (Commencement No. 3) Regulations 2025). That gave the CMA direct enforcement powers over consumer law. It can now issue fines of up to 10% of global annual turnover for breaches, without having to go through the courts first (CMA200 Direct consumer enforcement guidance).
Then in January 2026 the CMA published fresh guidance on supply-chain responsibility for green claims, tightening what a retailer, brand or manufacturer is expected to check about the claims made further up their supply chain (Making green claims: getting it right, across the supply chain).
Add to that a run of ASA rulings that have quietly narrowed what a business can say about aviation, oil, and consumer goods, and a pattern emerges. The regulators are not writing new rules. They are enforcing the existing ones with more teeth, more often, and against bigger names. You do not need to be Virgin Atlantic or Shell for this to matter. The tests they lost apply just as cleanly to a 30-person consultancy or a family-run manufacturer.
The 5 claim types most likely to land you in trouble:
1. "Net zero"
Commonly written: "We are a net zero company by 2030."
Why it fails: Net zero is a specific technical position: deep reductions across scopes 1, 2 and 3, aligned with a 1.5°C pathway, with residual emissions balanced by permanent removals. Very few businesses can substantiate that. Claiming it without a validated science-based target and a credible removals plan is one of the CMA's classic examples of a misleading claim (CMA, Green Claims Code).
Defensible rewrite: "We have committed to reach net zero by 2030 in line with the Science Based Targets initiative, and publish our progress annually."
Only use that rewrite if the commitment is real and the SBTi validation exists. Otherwise, replace the word "net zero" with "carbon reduction plan" and describe the plan. If you're not sure which term applies to your business, our guide to the difference between net zero and carbon neutral is the place to start.
2. "Sustainable"
Commonly written: "Made from sustainable materials."
Why it fails: "Sustainable" is, in the ASA's view, close to meaningless without qualification. Which impact is being reduced? By how much? Compared to what? A claim of sustainability that cannot answer those three questions is almost always deemed misleading.
Defensible rewrite: "Made from FSC-certified paper, sourced from forests managed to Forest Stewardship Council standards." Or, if the claim relates to recycled content: "Made from 80% post-consumer recycled polyester, certified to the Global Recycled Standard."
The pattern is the same. Name the property. Name the standard. Attach a number.
3. "Eco-friendly"
Commonly written: "Our eco-friendly cleaning products."
Why it fails: Same problem as "sustainable", written smaller. It suggests overall environmental benefit without evidence of one. The CMA specifically warns against catch-all green language of this kind.
Defensible rewrite: "Formulated without phosphates, palm oil or optical brighteners, and packaged in 100% recycled plastic." If those things are true.
4. "Recyclable"
Commonly written: "Fully recyclable packaging."
Why it fails: The Code requires you to consider the whole life cycle and the practical reality for the consumer. A product that is technically recyclable but that most UK councils will not accept at kerbside is, in the CMA's terms, functionally not recyclable for the person buying it.
Defensible rewrite: "Recyclable in kerbside collections across most UK local authorities, following the OPRL 'Recycle' label." Or, more cautiously: "Recyclable at supermarket soft-plastic collection points."
Precision saves you here. Vagueness costs you.
5. "Offset"
Commonly written: "We offset all our flights."
Why it fails: The Virgin Atlantic ruling in August 2024 sharpened this considerably. Any offset claim that does not specify what has been offset, through which project, verified against which standard, and how much residual emission remains, invites challenge (ASA, travel marketing: environmental claims).
There is also the language problem. "Offset" as a verb implies that the emissions have been undone. High-integrity carbon credits do not undo emissions. They finance verified reductions or removals elsewhere.
Defensible rewrite: "For every business flight we take, we finance an equivalent volume of verified carbon credits through a Gold Standard removal project, alongside a rolling reduction target for our travel emissions."
The rewrite matters commercially, too. It signals that you know the difference between an avoidance credit and a removal credit, which is increasingly what serious buyers, tender writers, and journalists are looking for. For more on that distinction, see our fuller piece on greenwashing.
What a defensible claim actually needs behind it
Here is the practical bit that most guidance skips. If a regulator, a journalist, or a large customer asked for the evidence sitting behind your environmental claim tomorrow, what would you send them?
This is the checklist CNB works through when we review a claim for a certified partner. It is not the whole file. It is the minimum.
A written scope. What is the claim about? The whole business, one product, one flight, one financial year? Vague scope is where most claims begin to fail.
A measurement. A greenhouse gas inventory calculated to a recognised methodology, usually the GHG Protocol, covering the relevant scopes. Dated. Attributable to a named person or organisation.
A reduction plan. What is being done to bring the number down, over what period, with what interim milestones. A claim of any kind of neutrality without a live reduction plan is now the fastest way to attract a complaint.
The offsetting or removal evidence. Registry name, project ID, vintage, retirement records. If you cannot show a serial number, you cannot show a claim.
The standard the claim is being made against. ISO 14068-1:2023 for carbon neutrality, SBTi for science-based targets, PAS 2050 for product footprints. Naming the standard shifts the claim from opinion to verifiable statement.
The date the evidence was last reviewed. Environmental claims decay. A carbon neutrality claim from a 2022 inventory that hasn't been touched since is not defensible in 2026.
If your file is missing more than one of those six, treat the claim as at risk.
The one sentence that quietly protects you
Almost every environmental claim can be made safer by changing the verb. "Is" is the dangerous one. "Is carbon neutral", "is sustainable", "is eco-friendly". These are absolute statements, and the regulator will test them as absolutes.
The safer verbs are the qualifying ones. "Certified against". "Verified by". "Measured to". "Financed through". "Aligned with". These verbs point at evidence rather than making a claim about the state of the world.
Compare:
"Our business is carbon neutral."
"Our operational emissions are measured annually and financed to carbon neutral status under the Carbon Neutral Britain certification."
The second sentence is not a marketing improvement. It is a legal one. It moves the claim from a promise about reality to a description of a documented process, which is much easier to defend if someone asks you to prove it.
You can find the standard we work to in our guide to the ISO 14068 standard that now underpins carbon neutral claims.
CNB's view
The Green Claims Code is not a threat to businesses doing this work carefully. It is a threat to businesses doing it carelessly.
That distinction matters, because the honest response to tighter enforcement has been misread as "say less". A lot of good British businesses have quietly stopped talking about their climate work over the past two years because they are worried about getting it wrong. That is the wrong lesson.
The right lesson is: say more, but say it more precisely. Name the standard. Attach the number. Show the workings. Reduction and verified climate finance can, and in our view should, run alongside each other, and both hold up better under scrutiny than they used to.
Scrutiny is not a reason to abandon environmental claims. It is a reason to make them properly.
When we review a claim for a certified partner, most of the work is not adding legal disclaimers. It is helping the business say the thing it is actually doing, in a way a regulator would recognise as accurate. That is what our certification process for UK businesses is designed to do.
Conclusion
The Green Claims Code has not become harder to understand. The consequences of ignoring it have become harder to shrug off.
If the language on your homepage was written before April 2025 and no one has looked at it since, this weekend is a good time to look. Six words to search for: neutral, net zero, sustainable, eco, recyclable, offset. Where you find them, read the sentence they sit in, and ask whether you could send the evidence to a regulator on Monday morning without flinching.
If the answer is yes, you're fine. If the answer is "probably", you have some tidying to do. And if the answer is "I have no idea", that is a conversation worth having sooner rather than later. Careful language is not the enemy of climate ambition. It is what makes climate ambition credible.
If you want to go deeper on the wider pattern behind these rulings, we've written a longer piece on greenwashing and how UK regulators are responding.
Can we still say "carbon neutral"?
Yes, if you can substantiate it. The claim survives when it is tied to a named standard (such as ISO 14068-1:2023), a documented inventory, a live reduction plan, and verified carbon credits with retirement records. Without those, it does not.
Do we have to name our verification body?
The Code does not mandate it, but the CMA's supply-chain guidance from January 2026 makes clear that businesses are expected to be able to show the basis of any environmental claim on request (CMA, supply-chain guidance). Naming the verification body in public copy is one of the simplest ways to demonstrate that, and it now looks conspicuous when a claim is made without one.
Does the Green Claims Code apply to LinkedIn posts?
Yes. The Code applies wherever a business makes an environmental claim to consumers or potential customers, and the ASA has taken action on organic social posts before. Corporate LinkedIn content is not exempt because it is not a paid ad. If a claim would fail on your website, it will fail on your LinkedIn feed.
What happens if a supplier's claim turns out to be wrong?
The CMA's January 2026 supply-chain guidance is explicit: businesses are responsible for the environmental claims they pass on to their customers, even when the underlying data comes from a supplier. Reasonable checks, documented, are the expected standard. "Our supplier told us" is not, on its own, a defence.
Is the DMCC Act being enforced yet in 2026?
The CMA's direct consumer enforcement powers came into force in April 2025 (Commencement Regulations). The Authority has been publishing enforcement guidance and testing the powers through investigations rather than immediately reaching for the maximum 10% turnover fines. Treat that as a warning shot rather than a reprieve. The powers are there. The question is when, not whether, they get used on a greenwashing case.
Does buying "green" cloud offset my AI emissions?
Not automatically. A supplier's renewable energy claim, an offset arrangement or a "carbon neutral" cloud badge can be part of the picture, but they need underlying evidence: matched-hourly renewables, verified retirement records, independent assurance. Without that, the safer position is to report the gross figure and note the supplier's own claims separately.
