General information, not legal advice. This chapter summarises published regulator guidance in plain language. For a decision that matters, read the cited documents and talk to a qualified adviser.
Two systems that work together
In the United Kingdom, affiliate content is shaped by two overlapping systems.
- Advertising self-regulation. The Committee of Advertising Practice (CAP) writes the UK Code of Non-broadcast Advertising and Direct and Promotional Marketing, usually called the CAP Code. The Advertising Standards Authority (ASA) applies it, considering complaints and publishing rulings. CAP and the ASA also publish advice on how the Code applies to particular situations, including affiliate marketing and influencer posts.
- Consumer protection law. Parliament sets the law on unfair commercial practices, most recently in the Digital Markets, Competition and Consumers Act 2024. The Competition and Markets Authority (CMA) is one of the bodies that enforces it, and it has published guidance for people who post endorsements on social media.
The two systems ask a similar question in different words: would people realise they are looking at marketing, and would they be misled if they did not? A publisher who meets the ASA's labelling expectations is usually well placed under the consumer law as well, though the two are separate.
The CAP Code: marketing must be recognisable
Section 2 of the CAP Code is titled "Recognition of marketing communications". Paraphrased, its core rules are:
- Marketing communications must be obviously identifiable as such.
- Marketers must not falsely claim or imply that they are acting as a consumer, or for purposes outside their business.
- Marketing must make clear its commercial intent, where that is not obvious from the context.
- Where marketing appears alongside editorial content, as in an advertisement feature, it must be clear which is which.
The thinking behind these rules is the same as the US idea of a material connection. People treat independent opinion differently from advertising, so they should not be left to guess which one they are reading.
CAP advice on affiliate content
CAP's advice on online affiliate marketing explains how the Code applies when a publisher is paid through affiliate links. In summary, affiliate content can be a marketing communication, because the publisher has a financial interest in readers buying, and where it is, the Code's rules apply to it in the same way as to any other advertising. The most important consequence is the rule in Section 2: readers must be able to tell that the content is marketing.
The advice also explains that whether a particular piece of content is caught depends on the facts, such as how closely the content is connected to the affiliate arrangement. That is a reason to read the advice itself rather than rely on a summary. For a typical affiliate post whose purpose is to send readers to buy, the safe working assumption is that it needs to be identifiable as marketing.
Labels the ASA expects
The ASA and CAP publish an "Influencers' guide to making clear that ads are ads". Although written for social media, it is the clearest UK statement of what a good label looks like, and it covers affiliate content. Its main points, paraphrased, are:
- Affiliate content is advertising. The guide treats posts that include affiliate links or codes, where the creator earns from sales, as advertising that needs to be labelled, even when the creator chose what to say.
- Label it upfront. The label should be seen before people engage with the content, not only after they have read or watched it or clicked through to it.
- Use a clear label. The guide recommends a plain identifier such as "Ad" and warns that vaguer terms, abbreviations or labels hidden among other text may not make the commercial nature clear.
- Make it prominent. The label should stand out and should not be lost among hashtags, buried at the end, or visible only after expanding the text.
- Platform tools may not be enough on their own. Built-in labels can help, but the guide advises checking that the result is clear enough on its own.
Example (invented)
A short video reviewing a kitchen gadget includes a discount code that earns the creator a commission. Under the ASA's approach, a clear "Ad" label at the start of the caption, and an on-screen or spoken mention at the start of the video, would make the commercial nature obvious. A line saying "code in bio" at the end of a long caption would not.
CMA guidance for content creators
The CMA's guidance, published on GOV.UK as "Social media endorsements: guidance for content creators", explains the consumer law position for people who post about products. Its main points, paraphrased, are:
- Be open whenever you have been paid, given gifts or loans, or received any other incentive connected with a post. Hiding that connection can break consumer protection law.
- Make it clear upfront and prominently, so that people see it straight away, rather than relying on them to find it.
- Do not mislead people about your experience of a product, for example by implying you have used something you have not, or by presenting a paid post as a spontaneous opinion.
- Responsibility is shared: brands and agencies working with creators also need to make sure posts are clearly labelled.
The CMA's guidance overlaps heavily with the ASA's. The difference is mainly in the enforcement route: the ASA applies an industry code, while the CMA enforces the law.
The consumer law underneath
The Digital Markets, Competition and Consumers Act 2024 contains the current UK rules on unfair commercial practices. It prohibits practices that mislead consumers by action or omission and that are likely to change their decisions. It also includes a schedule listing commercial practices that are treated as unfair in all circumstances, without needing to show that any particular consumer was affected. That list includes practices relevant to affiliate publishers, among them paying for promotion within editorial content without making that clear, and practices involving fake or misleading consumer reviews.
A statute is harder to read than guidance, and this handbook does not attempt a legal analysis of it. The practical point for publishers is that hidden advertising and fake reviews are not only matters of good practice in the UK: they are covered by the law, and the CMA's guidance explains how it sees them.
How the UK compares with the US
| Topic | United States (FTC) | United Kingdom (ASA, CAP, CMA) |
|---|---|---|
| Core test | Disclose a material connection people would not expect | Marketing must be obviously identifiable as marketing |
| Typical label | Plain words, for example that you earn commission | A clear upfront label such as "Ad" |
| Placement | Clear and conspicuous, near the claim or link | Upfront and prominent, before people engage |
| Main documents | Endorsement Guides, FAQ, Disclosures 101 | CAP Code Section 2, ASA and CAP advice, CMA guidance, the 2024 Act |
The emphasis differs a little. US guidance focuses on explaining the relationship in plain words; UK guidance focuses on labelling the content as advertising. A publisher with readers in both countries can meet both by labelling the content clearly at the start and explaining the commission in plain words near the links. Chapter 04 shows how.