Outbound calling in the UK: the Ofcom and ICO rules your dialler has to follow

Two regulators watch outbound calls into the UK. Ofcom cares about how your dialler behaves — silent calls, abandoned calls, the number you show. The ICO cares about whether you should be making the call at all. Most teams that get into trouble were fine on one and never looked at the other.

Two regulators, two questions

Ofcom uses its persistent misuse powers under the Communications Act 2003. Its question is about behaviour: did your calls leave people answering to silence, hanging on a line nobody was on, or unable to tell who rang them?

The ICO enforces the Privacy and Electronic Communications Regulations, PECR. Its question is about permission: were you allowed to make that marketing call to that number in the first place?

A campaign can pass one test and fail the other. A perfectly tuned dialler calling numbers on the TPS is still breaking the law, and so is a clean, screened list dialled so hard that a fifth of the people who answer hear nothing.

Silent and abandoned calls

A silent call is one where the person answers and hears nothing. An abandoned call is one where they answer and no agent is free to take it. Both are a side effect of predictive dialling, which rings more numbers than you have agents on the assumption that most will not answer. When more people answer than expected, somebody gets dropped.

You will still see a figure of 3% quoted as the safe limit. It comes from Ofcom’s older guidance, and it is out of date. Ofcom’s revised policy, in force since March 2017, does not treat any abandoned-call rate as a safe harbour: any silent or abandoned calling can be persistent misuse, and Ofcom is more likely to act the more such calls you make and the higher the rate. Treat 3% as a ceiling to stay well below, not a target.

Three practices still sit at the centre of what Ofcom expects:

• An information message on every abandoned call. Short, recorded, and it must say who was calling and give a number to contact you on. No sales content in it.
• The 72-hour rule. Once a number has had an abandoned call, call it again within the next 72 hours only with a live agent guaranteed to be there.
• Honest counting of answering-machine detection. When AMD mistakes a person for a machine and drops them, the person heard a silent call. Count those false positives in your figures, because to them that is exactly what happened.

The number you show

For a marketing call you must not withhold your number. The ICO expects the person to see a number they can call back, and Ofcom expects that number to be valid, dialable and one you are entitled to use.

UK networks also block calls arriving from abroad that display a UK landline number, apart from a small number of legitimate cases, which matters a great deal if your team is offshore. The detail is long enough for its own article: which number your outbound calls should show.

TPS and CTPS

The Telephone Preference Service is the register people join to opt out of sales calls. There are two registers, and screening against only one is the most common mistake:

• TPS covers individuals — and sole traders and most partnerships, because in law they are individuals rather than companies.
• CTPS covers companies and other organisations.

You cannot make a live marketing call to a number on either register unless that person or business has told you they are happy to receive your calls. A new registration takes effect after 28 days, so screen every calling list against both registers at least every 28 days, and keep your own do-not-call list for anyone who has asked you directly to stop.

Recorded-message marketing calls are stricter still: they need the person’s specific prior consent whether or not they are on the TPS.

What it costs to get wrong

Since 5 February 2026, under the Data (Use and Access) Act 2025, PECR fines can reach £17.5 million or 4% of global annual turnover, whichever is higher. For more than twenty years the ceiling had been £500,000. Most fines are far smaller than the maximum, but the ICO can also issue an enforcement notice that stops a campaign outright.

Ofcom can fine up to £2 million for persistent misuse. And there is a practical consequence that arrives before either regulator: networks and providers cut off customers whose traffic draws complaints, because the complaints land on them too.

A short checklist

1. Dialler abandon rate set conservatively, and reported per campaign per day.
2. Information message recorded, short, and tested on a real phone.
3. 72-hour recall rule enforced in the dialler rather than left to agents.
4. AMD false positives counted as abandoned calls.
5. A valid number you own on every call — and somebody answering when people ring it back.
6. Lists screened against TPS and CTPS within the last 28 days.
7. Your own do-not-call list, applied before every campaign.
8. Consent records kept for anything automated.

For the regulators’ own wording, see Ofcom’s review of its persistent misuse powers, the TPS site, and the ICO.