Copywriting services advertising rules: follow the CAP Code or the CMA?

What to take away

Yes. Both rulebooks applythe CAP Code, applied by the Advertising Standards Authority (ASA), and the Consumer Protection from Unfair Trading Regulations 2008 (CPRs).
The CPRs are enforced by the CMA and local Trading Standards. The ASA enforces the self-regulatory Code.
Hold dated evidence for every objective claim before the ad goes live.
The ASA normally gives an advertiser 10 working days to respond to a complaint, and publishes its ruling.
Penalties for unfair commercial practices can reach 10% of global turnover or £300,000, whichever is higher.

Why the CAP Code and the CPRs both apply

Both cover your ads. The Committee of Advertising Practice writes the CAP Code, and the ASA applies it to most non-broadcast advertising, including paid search, social posts, email and landing pages. The ASA advertising codes require copy that is truthful and not misleading.

The CPRs 2008 sit underneath as statute. They prohibit misleading actions and misleading omissions in business-to-consumer marketing across the UK. One claim can breach both, so two enforcers can take an interest in the same advertisement.

You follow the Code as you write, and you answer to the CMA or Trading Standards if the regulations are broken. Claims about results, rankings and client outcomes attract the most attention under both regimes.

Who enforces each regime, and what each can do

Who enforces each regime

Made by

CAP Code: Committee of Advertising Practice
CPRs 2008: Parliament

Enforced by

CAP Code: Advertising Standards Authority
CPRs 2008: CMA and local Trading Standards

Typical remedy

CAP Code: Ad amended or withdrawn, ruling published
CPRs 2008: Undertakings, court orders, fines up to 10% of global turnover or £300,000

The two rulebooks overlap in scope but differ in remedy.

CAP Code vs CPRs

CAP Code

Who writes it: Committee of Advertising Practice
Who enforces: Advertising Standards Authority
Scope: Paid search, social, email
Remedy: Change or withdraw ad

CPRs

Who writes it: UK statute
Who enforces: Competition and Markets Authority
Scope: Business-to-consumer marketing
Remedy: Undertakings, court action

The CMA's consumer protection role includes accepting undertakings and bringing court action on behalf of consumers. The CMA can also impose direct penalties for unfair commercial practices, up to 10% of global annual turnover or £300,000.

The Consumer Protection from Unfair Trading Regulations 2008 carry criminal liability too. The most serious breaches, including misleading actions, can bring an unlimited fine, up to two years in prison, or both. Local Trading Standards services bring most of those prosecutions.

To see how self-regulation and statute fit together for writers, the UK rules and compliance guide for copywriting services maps each rulebook to the work it catches.

Example: one claim, rewritten

Why it fails

Guaranteed first-page rankings in 30 days: An absolute guarantee that cannot be evidenced for every client
The UK's leading copywriting agency: Superlative comparison with no stated basis
Double your conversions: Typical-result claim resting on a single project

Rewritten wording

Guaranteed first-page rankings in 30 days: Three target keywords reached page one, supported by dated analytics
The UK's leading copywriting agency: Rated [x] out of 5 by [n] clients between [month] and [month]
Double your conversions: Conversions rose by [x]% for [sector] over [period], measured in [tool]

Replace every bracketed item with your own dated figures before publishing. A rewrite only holds up if the evidence file exists behind it.

Checklist: what to hold before the ad runs

Checklist before the ad runs

Dated evidence for each objective claimanalytics exports, test data, survey sources.
Written consent from named clients before using their results or their words.
A stated basis and measurement date for any comparison or superlative.
Pricing claims checked against your current fee schedule and VAT treatment.
Dated screenshots of the live ad as published.

Client stories are where evidence problems usually start. The guide to case study writing services in the UK covers consent, sign-off and the gap between a typical result and a one-off.

What happens after the ASA upholds a complaint

The ASA asks the advertiser to respond, normally within 10 working days. If it upholds the complaint, the ruling is published and the ad must be amended or withdrawn.

Repeat breaches escalate. The ASA Compliance team monitors the advertiser and shares ad alerts with platforms. Paid search ads can be removed through the ASA's agreements with Google and Bing, and persistent offenders can be referred to Trading Standards or the CMA.

Data, contracts and client material

Sending client data to a platform, CRM or partner agency brings in the UK GDPR. You need a lawful basis, a written arrangement and a retention period, and the ICO publishes guidance on sharing data between organisations.

Contract terms decide who corrects a challenged claim and who pays. Approval rights, indemnities and payment schedules belong in writing, as set out in commercial contracts for copywriting services.

This article is general guidance for England, not legal advice.

Common questions

Do the CAP Code and the CPRs both apply to copywriting ads?

Yes. The ASA applies the CAP Code, and the CMA and Trading Standards enforce the CPRs. A single ad can breach both.

What evidence do I need before publishing an objective claim?

Dated, verifiable records such as analytics exports, test results, invoices or survey data, held before the ad runs. The ASA expects the advertiser to substantiate the claim when asked.

What can the CMA or Trading Standards actually do?

They can accept undertakings, seek court orders, and impose or pursue penalties, including up to 10% of global turnover or £300,000 for unfair commercial practices. Serious misleading actions can be prosecuted.

Does UK GDPR apply when I share client data for a campaign?

Yes. Passing personal data to a partner, platform or client needs a lawful basis and a documented arrangement. Record the purpose and the retention period.