Greenwatching: Which? publishes a study on compliance with the CMA’s Green Claims Code in the UK

Which? has recently published a study analysing the compliance of green claims online with the CMA’s Green Claims Code in the UK. The study concludes that that although only around a fifth of product descriptions reviewed included a green claim, the consumer association considers many green claims made by businesses could fall short of compliance. 

We take a closer look at the findings of the Which? study, what it could mean for CMA enforcement, and top compliance tips for businesses below.

The Green Claims Code

Published by the CMA in 2021, the Green Claims Code (the “Code”) provides businesses with a principle-based model to guide compliance efforts. The principles (detailed in our previous blog) are that claims:

• Are truthful and accurate;
• Are clear and unambiguous;
• Do not omit or hide important information;
• Compare goods or services in a fair and meaningful way;
• Consider the full cycle of the product or service; and
• Are substantiated.

Since 2021, the CMA has regularly provided more detailed guidance, including examples, across the fashion and heating industries specifically. 

The CMA has taken a mixed approach to consumer enforcement of green claims – agreeing undertakings with ASOS, BooHoo and George, sending warning letters to fashion companies for non-compliance and agreeing undertakings with Worchester Bosch concerning green claims in heating and insulation. On the other hand, the CMA ultimately dropped the investigation into green claims launched against Unilever.

The Which? study

The study employed a large language model AI system (OpenAI’s GPT-4o) to analyse a total of c.20,000 product descriptions across 32 websites (9 multi-brand retailers, and 23 own-brand retailers), eventually selecting a subset of 1,000 products with green claims for more detailed analysis. 

Of the subset, only 16% of green claims were assessed to be fully compliant with the Code, whilst 62% were considered to fall short of compliance with at least two of the Code’s principles. 

The study analysed the failure rate by principle (noting they were not able to assess whether claims were truthful, or whether they omitted or hid important relevant information): 

• 1 in 5 products failed a check under the principle that claims must be accurate. Failed checks included that the percentage of organic materials was not clearly specified, caveats and conditions were not clear and easy to understand or contradicted the claims, or obvious unrealistic claims about recycling were made.
• Nearly two-thirds of products failed a check that claims must be clear and unambiguous. Reasons for this varied by product (and not all products were assessed against each check), but generally claims failed where vague or general terms were not justified, explained, or evidenced; technical terms or visual elements like logos or badges were not explained; caveats on compostability or biodegradability were not made clear; or the goals of the business were not distinguished from product-specific claims. 
• 86% of products with a comparative green claim failed a check for making a fair and meaningful comparison. Although only 85 of the 1,000 subset made a comparative green claim, the vast majority of these claims failed to provide evidence to support this comparison. Other issues included lack of clarity on what was being compared, or failure to compare the same measures and attributes. 
• Over three in five products failed a check that claims must be substantiated. The primary issue related to failure to provide links, QR codes or references where no evidence was provided on the product. A smaller subset failed to provide evidence from a credible or recognised source, or which was current and not outdated. 
• 88% of claims were found to consider the full lifecycle of the product. Only a small subset of products did not make clear what part of the product lifecycle the claim related to.

An impact on enforcement?

The CMA looks set to commence more large-scale, public enforcement from Autumn 2025. Whether the first investigations will include more detailed scrutiny of green claims remains to be seen, but this is certainly an area the CMA has considered in detail over recent years. The Which? report puts the spotlight on green claims and may well whet the appetite of a data-driven CMA, equipped with its own robust monitoring and analysis functions.

Whilst Ocado generally gets a good review in the Which? study, the inclusion of multi-brand retailers raises an important question around second-party publications of green claims. The final guidance on unfair commercial practices softened the burden of compliance concerning the new prohibition on fake reviews for second-party publishers, and it seems logical that the same approach should be taken in respect of green claims. To what extent will UK retailers have to stress-test their suppliers’ green claims, and how will this differ from the approach taken by the European Commission? Where liability will fall, and enforcement bite, remains to be seen. 

It’s important to acknowledge that the Code itself is not binding – it is guidance which reflects the CMA’s expectation of what it will consider an unfair commercial practice (i.e. a commercial practice which causes the average consumer to take a transactional decision which they would not otherwise have taken – for a breakdown of, and more detail on, these key terms, see our previous blog post). 

It’s not inconceivable that businesses might challenge aspects of the Code if the CMA were to launch an investigation in greenwashing. 

The Which? study and Code, for example, focus heavily on the requirement to substantiate green claims, subject to reasonable restrictions (e.g. packaging size).  Certain behavioural economics studies suggest that the proliferation of different labels and poor communication leads to customer confusion, meaning that requirements to substantiate green claims on packaging itself must be balanced with the net benefit to the average consumer. 

Similarly, the literature on consumer comprehension and memorisation around technical issues such as CO2 emissions and energy costs is mixed – businesses face a considerable challenge communicating complex green claims in a substantiated, simplified, brief manner especially if confined to a single package or even a webpage. 

Top compliance tips for businesses

• Avoid generic and vague terms such as ‘eco-friendly’ or ‘sustainable’ without some additional substantiation and detail. 
• Substantiation could look as simple as including a reference to a certification body and certification number, for example to justify claims which describe food as ‘organic’. In the absence of certification schemes, consider whether more detailed information on suppliers and industry initiatives could help inform consumers and substantiate the claims you are making. 
• Avoid technical language or acronyms which most consumers may misunderstand. 
• Be specific – is a product ‘biodegradable’ in all conditions, or only some? Can a product be ‘recycled’ anywhere, or only in a specific manner, or by following certain steps?
• Make comparisons clear – if you’ve reduced emissions or packaging, make sure it’s clear to the consumer the extent of the reduction (e.g. as a percentage), compared to the baseline (e.g. the same volume pack in 20XX, manufacturing emissions in 20XX). 

For more information on greenwashing in the UK and elsewhere, see our Greenwashing materials.