Ofcom rules for AI and automated outbound calls

The Definition of Persistent Misuse

Ofcom regulates automated outbound calling under the 'persistent misuse' provisions of the Communications Act 2003. Their Statement of Policy sets out specific expectations for any organisation using automated technology to contact UK consumers. For voice AI practitioners, this means the technology is not exempt just because it uses a Large Language Model (LLM) rather than a simple 'press 1' script.

Persistent misuse typically involves calling patterns that cause annoyance, inconvenience, or anxiety to consumers. In the context of voice AI, this primarily relates to silent and abandoned calls. Even if an AI agent is designed to be helpful, if the underlying telephony or orchestration layer fails to connect the call to a responsive agent (human or AI), it may fall foul of these rules.

The 3% Abandoned Call Threshold

One of the most critical metrics for outbound voice AI is the abandoned call threshold. Ofcom defines an abandoned call as one that is answered by a live person but no agent—human or AI—is available to take the call within two seconds of the person finishing their greeting.

Regulations state that the abandoned call rate must not exceed 3% of all 'live' calls made over a 24-hour period. While voice AI theoretically reduces the risk of traditional 'agent scarcity' abandoned calls, technical failures such as high latency in the STT (Speech-to-Text) layer or LLM inference timeouts can cause the AI to miss the two-second response window, effectively creating an abandoned call.

• Calculated over a 24-hour period per outbound campaign.
• Must exclude calls that are answered by answering machines (AMD).
• If a call is abandoned, the caller must be played a brief information message within two seconds.
• The number called must not be called again within 24 hours unless a live agent is guaranteed to be available.

Caller Line Identification (CLI) Presentation

Ofcom requires all outbound calls to present a valid, diallable CLI (Caller Line Identification). For voice AI deployments, this means the number displayed to the consumer must be one that the consumer can call back to reach the organisation or opt-out of future calls.

Using 'local presence' (displaying a local geographic number to increase answer rates) is permitted only if the number is authentic and under the caller's control. Presenting invalid numbers or numbers that do not accept return calls is a breach of the CLI guidelines and can lead to significant fines.

Silent Calls and AI Latency

A silent call is distinct from an abandoned call; it occurs when the caller answers, but hears nothing at all. In the voice AI stack, this is often the result of 'dead air' caused by high turn-taking latency or a total failure of the Text-to-Speech (TTS) engine.

Ofcom takes a particularly dim view of silent calls, as they are often associated with unscrupulous marketing or fraudulent activity. Practitioners must ensure that their AI agents have robust 'keep-alive' signals or immediate fallback mechanisms to ensure the caller is never left in silence. If the AI cannot generate a response, the system should ideally play the mandatory abandoned call information message rather than remaining silent.

Record-Keeping and Compliance Audits

Compliance cannot be proved after the fact without rigorous record-keeping. Ofcom expects organisations to maintain detailed logs of all outbound dialling activity for a minimum of six months. For voice AI, this includes not just the call logs, but the performance metrics that prove the 3% threshold was respected.

These records must be sufficient to show the outcome of every call attempt, the duration of any silence before the AI responded, and the handling of any abandoned calls (including the playback of the information message). In the event of an inquiry, Ofcom will request these logs to verify that the organisation's dialling practices do not constitute persistent misuse.