Dr Plastow said: "While carrying out this assurance review we were informed about the insufficient quality and resolution of Scottish images on the Police Scotland Criminal History System, which affects a portion of custody images captures between 2019-2024. "This means a sizeable portion of custody images are not searchable under PND facial search functionality. "This gap could mean that people who have had their custody image previously taken, are not being detected on future probe images uploaded by Police Scotland, which could lead to crimes not being detected." The report stated that the force said a "software issue" was causing the custody images to be captured at a lower than recommended minimum size. The images were then being additionally compressed using a technique that left them unsuitable for use with the PND.

On 18 July, the House of Commons select committee on science and technology published an assessment of the work of the biometrics commissioner and the forensic science regulator. My guess is that most citizens have never heard of these two public servants, which is a pity because what they do is important for the maintenance of justice and the protection of liberty and human rights. The current biometrics commissioner is Prof Paul Wiles. His role is to keep under review the retention and use by the police of biometric material. This used to be just about DNA samples and custody images, but digital technology promises to increase his workload significantly.

The "rapid" growth of a police facial recognition database could lead to innocent people being unfairly targeted, a watchdog has warned. Biometrics Commissioner Paul Wiles said the Police National Database (PND) now had at least 19 million custody photographs on it. However, it is thought that hundreds of thousands of these could be of innocent people. The Home Office said police should delete images of unconvicted people. In a government review published in February, the Home Office concluded that those who are not convicted should have the right to request that their custody image is deleted from all police databases.