Poor quality photos ‘could lead to crimes not being solved’

Poor quality photographs taken by Police Scotland of people they arrest could lead to crimes not being solved in the future, a report has warned.

Scottish Biometrics Commissioner Dr Brian Plastow said a “sizeable proportion” of custody images taken between 2019 and 2024 are of such low quality they are unsuitable to be used for facial searching purposes.

Police forces across the UK upload images of everyone they arrest to the police national database (PND), which allows officers to detect potential matches with photographs of suspects captured and uploaded from sources including video doorbells and CCTV.

The quality and resolution of any image uploaded can significantly impact the effectiveness of retrospective facial searches.

A joint report from the Scottish Biometrics Commissioner and His Majesty’s Inspectorate of Constabulary in Scotland has called on Police Scotland to improve the resolution of its custody images.

They say this must happen before Police Scotland can take part in any new facial matching services proposed for law enforcement purposes, including the potential use of live facial recognition technology.

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 states Police Scotland 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 within the PND for facial searching purposes.

Dr Plastow said: “Police Scotland should ensure this issue is solved, particularly considering the adoption of new systems such as the UK Home Office strategic facial matching project.”

The commissioner’s report – a joint assurance review of the use of retrospective facial search technologies for criminal justice and police purposes in Scotland – made four recommendations to Police Scotland.

It said Scotland’s national force should develop a bespoke policy on the use of retrospective image search technologies, and that it should conduct a training needs analysis for all officer and staff regularly working in this area.

It also said Police Scotland should improve the collection of data evaluating the effectiveness of such technologies and do more to promote public understanding of its value.

Dr Plastow said: “In an increasingly digital world, the future of law enforcement lies in achieving the right balance between the introduction of new technologies for public safety and safeguarding fundamental rights.

“For biometrics, public confidence should be maintained with transparency, robust governance and independent oversight.

“This, along with the issues highlighted in our report, should prompt significant reflection for policing in Scotland.”

Assistant Chief Constable Steve Johnson, of Police Scotland, said: “We will consider the Scottish Biometrics Commissioner’s recommendations in full and in the context of the development of our biometrics strategy, policy and standard operating procedures.

“Our biometrics oversight board is already aware of this issue and is overseeing work to improve the quality of images taken in custody and the collaboration with Home Office strategic facial matcher project, which mirrors the recommendations.”