The head of a Commons committee has questioned whether arrangements for storing millions of photographs on a vast police database could withstand a legal challenge.

Liberal Democrat MP Norman Lamb voiced concerns after it emerged forces have received only a handful of requests to delete “custody images” – pictures taken of individuals’ faces at police stations following arrests.

Hundreds of thousands of innocent people were given the green light to ask for their pictures to be erased under a Government review published last year.

But figures obtained by the Press Association indicate that only a small number have lodged applications.

Custody image removal requests(PA Graphics)

Mr Lamb, chairman of the Commons Science and Technology committee, said the current arrangements “appear to allow images of people who don’t have convictions nor are suspected in live police investigations to be kept by the police until an application is made for deletion”.

He added: “Then, there is no guarantee that it will be deleted if the police think there are good ‘police purposes’.

“There must be significant doubt as to whether this would survive a legal challenge.

“My concern is that the Government may be maintaining an unlawful policy.”

The Government insists its policy complies with the law.

There are around 21 million images on the Police National Database (PND), 12.5 million of which have been enrolled in a gallery which can be searched using facial recognition software.

These totals include cases where multiple images of the same individual are held.

There is no precise figure for the number of pictures of innocent people held on the PND but it is believed to run to hundreds of thousands.

In February last year a Home Office review concluded that those who are not convicted should have the right to apply for the deletion of their custody image from all police systems.

At the weekend the Press Association revealed how figures from 37 out of 43 forces in England and Wales, obtained following Freedom of Information requests, show 67 requests for custody image removals were received in just over eight months after the review was published.

As of the end of October, 34 of the requests had been accepted and images deleted. Fourteen were refused, while 19 were ongoing.

A Home Office spokeswoman said: “Following the custody image review, published in 2017, individuals who have been arrested but who are not subsequently convicted of an offence have the right to request that their custody image is deleted from all police databases, with a presumption that it will be unless there is an exceptional policing reason for it to be retained, such as if the individual has known links to organised crime or terrorism.

“Where the person does not request deletion, the police should review retention of their image in line with scheduled review periods set out in the College of Policing’s Authorised Professional Practice to ensure that they are only retaining those they need to keep.”

Police chiefs have said the custody images database helps identify potentially harmful suspects and keep the public safe.