Retrospective Facial Recognition (PND search)

Retrospective facial recognition against the Police National Database takes an image of an unknown person — from CCTV, a phone, a doorbell camera or social media — and searches it against custody photographs held nationally. It is the highest-volume facial recognition activity in UK policing and the least visible, because nothing happens in public.

More than 25,000 searches are run each month against a pool of over 19 million custody images.

THE BIAS FINDING

In December 2025 the National Physical Laboratory published an accuracy and equitability evaluation of the Cognitec algorithm used for these searches. The Information Commissioner's Office described the outcome without ambiguity in August 2026: bias in the algorithm increases the likelihood of incorrect matches for people in some demographic groups.

The response is recorded rather than the criticism alone. The Home Office and the National Police Chiefs' Council put mitigations in place — staff training, oversight reporting and equality impact assessments — alongside plans to replace the algorithm. The ICO continues to engage with HMICFRS, the Home Office and the NPCC on that replacement, and has reserved the right to take further regulatory action.

This is one of the few instances in this catalogue where an independent evaluation found a demographic disparity, a regulator stated it plainly, and the operator committed to replacing the system. That sequence is worth acknowledging even while the underlying finding stands.

THE CUSTODY IMAGE PROBLEM

The searchable pool is the long-standing controversy. Custody images are taken on arrest, and arrest is not conviction. Images of people never charged, or charged and acquitted, have historically remained in the collection, and the practical burden of removal has fallen on the individual to request it. Nineteen million images is a substantial fraction of the adult population of England and Wales.

Every retrospective search therefore runs against a gallery containing large numbers of people who were never convicted of anything.

THE LEGAL POSITION CHANGED IN 2026

Accounts describing an absence of any statutory framework are now out of date. The Crime and Policing Act 2026 opened police access to DVLA driver records including photographs. In March 2026 the House of Lords rejected an amendment that would have blocked facial recognition searching of the roughly 50 million image DVLA database, by 123 votes to 40.

The substantive framework governing which non-police galleries may be searched has been deferred to a further Police Reform Bill. A Home Office consultation on the facial recognition framework closed on 12 February 2026 with a government response promised within twelve weeks; that response remained unpublished more than three months past its due date as of August 2026, with the Home Secretary pressed on the delay in the Lords in July.

THE CASE FOR IT

The investigative value is straightforward and well evidenced by forces. Without it, identifying a suspect from a CCTV still can take around fourteen days; with it, minutes. That is not a marginal efficiency in a volume crime investigation.

It is also the least intrusive of the three facial recognition modes in one specific sense: it processes an image police already hold in connection with an actual incident, rather than scanning uninvolved members of the public. The NPL evaluation found retrospective use performed at a 100% true positive identification rate with no significant demographic difference in its overall assessment — a finding that sits alongside, and in tension with, the ICO's statement about the algorithm's bias, and both are recorded here.

THE CASE AGAINST

Searching a gallery of unconvicted people is the central objection, and it is not answered by algorithmic improvement. Retention of custody images of people never charged has been criticised for years without being resolved.

The DVLA expansion is a categorical change rather than an incremental one. A custody image collection contains people who have at least been arrested. A driving licence database contains people who have done nothing but apply to drive, and searching it makes the great majority of adults biometrically identifiable to police.

Invisibility compounds both. Live facial recognition is at least apparent to those near a van. A retrospective search happens without the subject knowing, and there is no mechanism by which a person learns their image was searched.

WHAT IS NOT ESTABLISHED

Whether the algorithm replacement has begun, and what will replace it, is not established.

How many searches result in a correct identification, a wrongful one, or no match is not published.

How many of the 19 million custody images belong to people never convicted is not published.

The Home Office consultation response remained outstanding as of August 2026.