Who: The Committee of Advertising Practice (CAP)
Where: United Kingdom
When: 25 September 2025
Law stated as at: 30 October 2025
What happened:
CAP has published a series of guidance notes on environmental claims directed at each of the homes, cruise and aviation industries. This is the latest step in a broader regulatory push to ensure that sustainability-related claims are accurate, clear and can be substantiated.
Together, the guidance notes reiterate the core expectations for all environmental claims, namely that:
- Absolute or unqualified terms such as “green”, “eco-friendly” and “sustainable” should not be used unless it can be evidenced that the product, service or business in question has no negative impact, or a positive impact on the environment across its full life-cycle.
- The basis of a claim must be clear to consumers.
- Advertisers must hold robust substantiation to justify all claims.
Each individual guidance note also provides industry-specific examples to reiterate how advertisers can ensure that they are compliant with the UK Code of Non-broadcast Advertising and Direct and Promotional Marketing (CAP Code) across their respective sectors.
Green homes
For those in the homes industry, CAP has set out six tips that advertisers should follow to fall on the right side of the CAP Code. Marketing teams in this sector must:
- Evidence any unqualified claim, such as “sustainable” or “environmentally friendly”, with a full life-cycle analysis from manufacture to disposal that demonstrates no negative impact on the environment.
- Avoid absolute, exaggerated or ambiguous terms and, instead, use clear, qualified claims and/or comparative statements.
- Be upfront with their commercial intentions, particularly those using customer information to generate leads. For example, if an ad promoting a solar funding scheme or grant suggests that consumers qualify for free or subsidised solar panel installations, it should avoid creating the impression that the lead-generating company is a solar panel installation company or government funding scheme.
- Quote accurate and realistic price claims and include any necessary qualifications in relation to packages and complexities.
- Hold robust evidence, including in relation to end-of-life or green disposal claims, such as “plastic free” or “recyclable”.
- Include all material information relating to government funding eligibility criteria for installations of heat pump, solar panel and insulation in the ad itself.
Cruises
For those keen to market their green credentials in “sustainable cruising”, CAP has warned that broad claims, such as “uses new green technologies” or “green alternative”, are absolute claims that must be comprehensively evidenced and substantiated.
A recent Advertising Standards Authority’s (ASA) ruling against Sunshine Cruise Holidays t/a cruise 1st demonstrates that all factors relevant to the environmental impact must be considered holistically. In an ad claiming that the propellor blades “mitigate the worst impacts of underwater noise”, although use of this new type of propeller reduced noise impact on marine life, it conversely discharged materials that could harm that marine life and ecosystems. The marketer had therefore exaggerated the environmental credentials of the ship. Similarly, in an ASA ruling against www.Cruise.co.uk Ltd t/a SeaScanner, which claimed that the use of liquified natural gas (LNG) made its ship “eco-friendly”, the ASA noted that while an LNG engine is often promoted as a fuel that is better for the environment compared with traditional fuel engines, producing and burning LNG still releases methane and CO2. The claims were therefore held to be misleading. (See this MarketingLaw article for more on these rulings.)
The key takeaway for advertisers making environmental claims in this industry or the travel industry in general is that they must explain all actual and potential environmental impacts of a product, service or component to their consumers clearly and consider its whole life cycle.
Aviation
The guidance directed at the aviation industry is notably proactive from CAP – it anticipates a growth in future advertising for sustainable aviation fuel (SAF) and establishes clear guidelines for these ads. This guidance has been issued in response to the UK government’s mandate, setting out that the proportion of SAF in the UK’s total jet fuel supply must be increased from 2% currently to 22% by 2040. CAP emphasises that the usual expectations for environmental claims apply to SAF claims and that advertisers must make the basis of their claims clear and be able to substantiate them. SAF is an example of a new technology that consumers are unlikely to have knowledge of and so, to ensure compliance, CAP advises that advertisers should:
- Acknowledge that while SAF produces reduced emissions over its full lifecycle, the emissions are still significant. Advertisers should therefore highlight any negative environmental impacts to present a balanced claim to the consumer (such information could be considered material information that will impact a transactional decision).
- Consider using direct comparisons with another of their products or a competitor’s product (“greener” or “friendlier”) rather than absolute claims like “eco-friendly” that are interpreted to mean that the product in question has no negative impact on the environment (a very high bar to substantiate).
- Narrow claims to a specific element of the process (for example, the flight only) or ensure that the full life-cycle of the fuel has been considered, including production and supply.
- Hold robust evidence to substantiate the above.
- Avoid describing SAF as the exclusive initiative of a single service provider, as its use is a legal obligation across the UK.
- Be specific about the mix of SAF in the fuel or include the specific percentages to avoid implying that a fuel mix contains more SAF than it actually does.
Why this matters
The housing, cruise and aviation industries are traditionally high greenhouse-gas emitting industries and, following the trend of consumers wanting to make increasingly eco-conscious choices, there has been an increase in new products and services that promise environmental improvements. In these guidance notes, CAP and the ASA are reiterating their position on misleading greenwashing and sustainability claims to regulate ads against overstating the environmental benefits or giving misleading impressions to consumers. Their focus on the travel and transport sectors may also hint at the next significant area of focus for the regulators. Advertisers should consider that, while alternative products may be better for the environment than traditional options in their respective sector, they still may not deliver a net-positive impact or no negative impact across their full life-cycle. The practical message for advertisers is, therefore, to ensure that they make the basis of all environmental claims transparent and that they hold evidence that fully substantiates them.
