UK Disclosure Rules: The ASA and CAP Code
UK ads must be 'obviously identifiable.' Affiliate links are always advertising, the word 'Ad' is required, and '#aff' is not enough.
In the United Kingdom, affiliate and influencer disclosure is governed by two parallel systems that demand the same thing. The first is the CAP Code, enforced by the Advertising Standards Authority (ASA). The second is consumer-protection law, now enforced by the Competition and Markets Authority (CMA) under the Digital Markets, Competition and Consumers Act 2024. This page covers the ASA/CAP side; see the CMA and DMCC Act for the legal side.
The core rule: obviously identifiable
Rule 2.1 of the CAP Code requires that marketing communications be “obviously identifiable as such.” The audience must be able to recognize content as advertising immediately, without having to click or otherwise interact with it. Rule 2.3 prohibits falsely implying the marketer is acting as an ordinary consumer.
Affiliate links are always advertising
The ASA’s position is unambiguous: affiliate links, including those in influencer social content, are always likely to be considered advertising — regardless of whether the brand gifted anything or had editorial control. Because the content is advertising, additional disclosure is required to make that obvious.
Labels that work — and that do not
Adequate
- “Ad”
- “Advert”
- “Advertising”
- “Advertisement”
- “Ad Feature” (advertorial)
Inadequate
- “#affiliate” / “#aff” (not widely understood)
- “Sponsored” / “#spon” (varied interpretation)
- “#collab”, “Gifted”, “In association with”
- “#BrandAmbassador”
- A brand tag, @-mention, or discount code alone
“Aff” and “affiliate” are not enough
ASA consumer research found understanding of “affiliate” and abbreviations like “Aff” is particularly low. Consumers do not reliably know these denote paid content. Use the explicit word “Ad.”
Shared responsibility
Both the brand and the influencer are responsible under the Code, even where the ad was created solely by the affiliate and even where the brand had no editorial control and gifted nothing. The ASA has ruled against content routed through affiliate storefronts that failed to identify itself as advertising, and has held that content can remain an ad even after a discount code has expired, because it stays commercial in intent.
The consolidated ASA/CAP “Influencer’s Guide” is the primary practical reference. For the statutory enforcement regime, continue to the CMA and DMCC Act.
Authoritative sources
Last reviewed July 2026. This page is general educational information, not legal or tax advice.