The short answer
A dialler that plays a recorded or pre-generated message needs the subscriber's prior consent under regulation 19 of PECR, whether the number is on the TPS or not and whether the subscriber is a person or a company. An AI agent that converses in real time is a grey case; the safe reading treats it the same way. A human agent making a live call through a predictive or auto-dialler is under regulation 21 instead: screen against TPS and CTPS, honour opt-outs, show a number. Ofcom's rules on silent and abandoned calls sit on top of that.
This is a plain-English summary of the regulations as published on legislation.gov.uk, not legal advice. For the wider picture of cold calling law, start with are cold calls illegal in the UK.
What regulation 19 says
Regulation 19(1) reads: "A person shall neither transmit, nor instigate the transmission of, communications comprising recorded matter for direct marketing purposes by means of an automated calling or communication system except in the circumstances referred to in paragraph (2)."
Regulation 19(4) defines the system. An automated calling system is one "capable of (a) automatically initiating a sequence of calls to more than one destination in accordance with instructions stored in that system; and (b) transmitting sounds which are not live speech for reception by persons at some or all of the destinations so called."
So the test has two parts. The system test is about capability: can it dial a list by itself, and can it play sound that is not a person talking. Most diallers can do both. The prohibition then bites on what actually goes down the line: "recorded matter" for marketing.
The exception in regulation 19(2) needs two things. The called line must be "that of a subscriber who has previously notified the caller that for the time being he consents to such communications", and the caller must not hide its number, or must present a number it can be contacted on.
Consent from every subscriber, TPS or not
Regulation 19(2)(a) says "a subscriber". It does not split individual subscribers from corporate ones, as regulation 22 does for email. A limited company that has never heard of you is covered in the same way as a household. The TPS and CTPS registers do not come into it: a clean screen gives you nothing under regulation 19, because the default is no, not yes.
Consent means the UK GDPR standard. Regulation 2 says consent "by a user or subscriber corresponds to the data subject's consent in the UK GDPR". A line buried in a privacy notice, or a box ticked for something else, will not carry an automated marketing call. I covered what valid consent looks like for a registered number in calling a TPS number with consent; under regulation 19 the bar applies to every number on your list.
A human on a dialler is a regulation 21 call
A predictive dialler that connects a person to a live agent passes the regulation 19(4) system test, but the marketing content is the agent talking, which is live speech, not recorded matter. That call falls under regulation 21:
- 21(1)(b): no unsolicited marketing call to a number "listed in the register kept under regulation 26". That register covers both individual numbers (TPS) and corporate numbers (CTPS); regulation 26(1A) requires corporate subscribers to register in writing.
- 21(1)(a): no call to a subscriber who "has previously notified the caller that such calls should not for the time being be made on that line". Your own do-not-call list is part of the legal test.
- 21(3): a number listed for less than 28 days before the call is not yet a breach of 21(1)(b).
- 21(A1): the caller must not withhold its number, or must present one it can be contacted on. This applies to solicited calls too.
The three common set-ups compare like this:
| Set-up | Regulation | What you need before dialling |
|---|---|---|
| Recorded or text-to-speech message played out by a dialler | 19 | Prior consent from the subscriber, any subscriber type |
| Human agent connected by a predictive or auto-dialler | 21 | TPS and CTPS screening, your own opt-out list, a visible number |
| AI agent that converses in real time | 19 on the conservative reading, 21 in any case | Consent and a visible number; on the regulation 21 reading alone, TPS and CTPS screening and your opt-out list |
The grey case: AI that holds a conversation
Newer AI agents do not play a fixed message. They listen, generate a reply and speak it back within a second. Two words in the regulation decide where they sit.
"Not live speech" in regulation 19(4)(b) is the easy one. Synthesised speech is not a person speaking live, so a system that dials a list and plays a generated voice passes the system test.
"Recorded matter" in regulation 19(1) is where the text runs out. PECR does not define it. One reading is that speech generated on the fly is not recorded, so regulation 19 does not apply and the call is an ordinary regulation 21 call. The other reading is that the purpose of regulation 19 is to keep machine-generated marketing off people's phones without their agreement, and a synthesised voice is exactly that. I have not found a published ICO decision that tests either reading against a conversational AI agent.
I would take the conservative reading and treat an AI voice agent as regulation 19: get consent before it dials. The downside of being wrong the other way is a penalty under the higher maximum, which since 5 February 2026 is £17.5 million or 4% of global turnover, and regulation 19 is one of the regulations it applies to.
Regulation 2 defines a call as "a connection established by means of a telephone service available to the public allowing two-way communication in real time". A conversational AI call is a call, so regulation 21 applies either way. The caller ID rule in 21(A1) covers every marketing call, solicited or not. If you rely on regulation 21 alone, every call without consent is unsolicited and needs the TPS and CTPS screen and your opt-out list.
Abandoned and silent calls: Ofcom's side
Predictive diallers dial more numbers than there are free agents. When too many people answer at once, some calls are dropped or answered with silence. That is mainly an Ofcom question, not a PECR one. It falls under Ofcom's persistent misuse powers in sections 128 to 131 of the Communications Act 2003. Section 128(5) treats use of a network as misuse where its effect or likely effect is "to cause another person unnecessarily to suffer annoyance, inconvenience or anxiety", and section 130(4) caps the penalty at £2,000,000.
Ofcom's statement of policy on persistent misuse, published 20 December 2016 and applying from 1 March 2017, says "Ofcom's current top priority is to tackle silent calls", and that silent calls usually happen when an automated calling system has "over-dialled". Three points from it matter for dialler settings:
- Calls left to ring "for less than 15 seconds before being terminated" are "likely to be subject to enforcement action".
- Ofcom is likely to treat a repeat call within 72 hours of an abandoned or silent call, without a guaranteed live agent, as an aggravating factor.
- The 3% abandoned call rate in the 2010 policy was "a criterion for prioritising cases", not a safe harbour. Ofcom declined to create one.
An information message on an abandoned call can reassure the person called but, in Ofcom's words, "does not prevent persistent misuse occurring". Read the current statement on Ofcom's site before you set your dialler's pacing.
What the call has to tell people
Regulation 24 sets out what goes with the call, and it differs by regulation. For an automated call under regulation 19, the recording must give your name and either your address or a freephone number. For a live call under regulation 21, you must give your name, and the address or freephone number only "if the recipient of the call so requests". An AI agent on the conservative reading should give all of it, in every call.
What changed in 2026
Regulation 19 itself is unchanged. Its last amendment was in May 2016, and legislation.gov.uk shows no outstanding effects. Two things around it moved on 5 February 2026 under the Data (Use and Access) Act 2025. The regulation 2 definition of a call now adds that "a reference to making a call includes a reference to attempting to establish such a connection", so a dialled attempt counts as making a call. And the maximum penalty rose from £500,000 to £17.5 million or 4% of turnover. The full list of changes is in the Data (Use and Access) Act and cold calling, and the regulations in order are in PECR explained.
One-line answer
A dialler playing a recorded or pre-generated message needs prior consent from every subscriber under regulation 19; a human on a dialler needs TPS and CTPS screening and opt-outs under regulation 21 plus Ofcom's abandoned-call limits; treat a conversational AI agent as both. The full set of rules we screen against is on our compliance page.