UK Advertising Rules — What the ASA and CAP Code Mean for Your Facebook and Google Ads

There are two separate rulebooks governing a UK advert, and most small businesses only know about one of them. The first is platform policy — what Meta or Google will allow, enforced automatically and usually resulting in nothing worse than a rejected ad. The second is the CAP Code, administered by the Advertising Standards Authority, which applies to UK advertising regardless of what any platform permits. The ASA is not a regulator most small businesses think about, largely because it has no power to fine. What it does have is the power to publish. Rulings name the advertiser, describe the complaint, and stay online permanently, which for a local business searchable by name is a meaningful consequence. This guide covers the parts of the CAP Code that catch ordinary businesses out, none of which are exotic.

The Rule Underneath Every Other Rule

Almost every ASA ruling against a small business reduces to a single principle: you must hold evidence for the claims you make, before you make them. Not evidence you could obtain if challenged — evidence you already have. This one idea explains the large majority of upheld complaints.

• 1"The best in Manchester" needs substantiation — Superlatives are objective claims in the eyes of the Code. Without evidence, this is straightforwardly misleading, and it is one of the most common phrases in UK small business advertising.
• 2"Award-winning" requires an actual award — Named, verifiable, and relevant. A directory listing badge is not an award, and this has been the subject of rulings.
• 3"Trusted by thousands" needs a real number behind it — If you cannot produce the figure, do not use the phrase. Vague scale claims are treated as claims, not as flourish.
• 4"Guaranteed results" is very difficult to sustain — Particularly in health, fitness, beauty and financial services. Unless the guarantee is genuine, unconditional and honoured, avoid it.
• 5"Number one" needs a source and a date — And the source must actually support the specific claim, not something adjacent to it.
• 6Opinion is fine, fact is not — "We think you will love it" is subjective and unproblematic. "The most effective treatment available" is a factual claim requiring evidence.

Pricing Claims Are Where Most Businesses Slip

Price is the most heavily scrutinised area for ordinary businesses, because it is where misleading advertising causes direct financial harm. The rules are stricter than most advertisers assume.

Testimonials, Reviews and Influencers

This area has tightened considerably and now involves the Competition and Markets Authority as well as the ASA, with the CMA having gained direct enforcement powers over fake reviews. It is worth taking seriously.

• 1Testimonials must be genuine and documented — You need to hold proof that the person exists and gave the statement. Invented testimonials are both an ASA breach and potentially a consumer protection offence.
• 2Fake or incentivised reviews are a serious matter — Writing your own reviews, paying for reviews, or suppressing negative ones falls under CMA enforcement, not just advertising standards.
• 3Paid partnerships must be obviously identifiable — "#ad" or the platform's paid partnership label, placed where it is seen before the content is consumed. Burying disclosure at the end of a caption is not sufficient.
• 4Gifted products count as payment — If you sent free product in exchange for coverage, that is a commercial relationship requiring disclosure, even with no money involved.
• 5You are responsible for what your influencers say — The advertiser is accountable for claims made on its behalf. Brief them on what may and may not be claimed, in writing.

Sectors With Additional Restrictions

Some categories carry rules well beyond the general Code, and these are the areas where small businesses most often advertise without realising there is a specialist regime.

• 1Health and beauty — Claims about treating medical conditions are tightly restricted, and only qualified professionals may advertise certain procedures. Before-and-after imagery is restricted for many treatments. This catches out aesthetics clinics constantly.
• 2Financial services — Advertising regulated products generally requires FCA authorisation, and specific risk warnings apply. This includes some credit and buy-now-pay-later promotion by ordinary retailers.
• 3Weight loss and slimming — A specific and strict set of rules covering claimable rates of loss, imagery, and who may advertise what.
• 4Alcohol and gambling — Extensive rules on content, tone and audience composition, including limits on the proportion of an audience that may be under 18.
• 5Children's advertising — Restrictions on directly exhorting children to buy, and on advertising certain food and drink products around children's content.

What Happens If a Complaint Is Upheld

Understanding the actual consequences helps calibrate how much attention this deserves — which is more than most small businesses give it, but less than the word "regulator" might suggest.

• 1The ruling is published with your name on it — Searchable, permanent, and often the first thing that appears when someone researches your business. This is the real consequence for most small advertisers.
• 2You must withdraw or amend the advertising — Usually the immediate practical outcome, and typically the end of the matter if you comply.
• 3Persistent non-compliance escalates — The ASA can work with platforms to have paid search advertising removed, and refers serious cases to Trading Standards or the CMA.
• 4Anyone can complain, including competitors — A single complaint can trigger an investigation, and complainants are not required to have been misled themselves.
• 5Complying early is straightforward — Most businesses that respond promptly to an ASA query resolve it without a published ruling. Ignoring correspondence is what escalates matters.

Common Mistakes

• 1Assuming platform approval means compliance — Meta and Google approving your advert says nothing about the CAP Code. They are entirely separate systems.
• 2Superlatives written without thinking — "Best," "leading," "number one" are factual claims requiring evidence, and they appear in an enormous share of small business advertising.
• 3Permanent sale pricing — Among the most consistently ruled-against practices, and very common in local retail and services.
• 4Undisclosed gifted collaborations — A genuine and growing enforcement area, and the advertiser carries the responsibility, not the creator.
• 5Copying a competitor's claims — Their advertising may itself be non-compliant, and "they said it too" is not a defence.

Nothing here is legal advice. The CAP Code is published in full and the ASA operates a free advice service for advertisers, which is worth using before a campaign rather than after a complaint.