A police force is “deeply sorry” after body-worn video footage recorded by its officers over a period of nearly three years was lost from its computer systems.

South Yorkshire Police said it has referred itself to the Information Commissioner’s Office after noticing “a significant and unexplained reduction in data stored on its systems”.

The force said it is now urgently working with experts to recover footage – filmed by officers as they attended incidents or engaged with the public and which, in some cases, could be used as evidence in court – recorded between July 2020 and May 2023.

An estimated 69 cases have been identified as potentially affected, a spokeswoman said.

She said the force is working closely with victims and the Crown Prosecution Service.

The loss is the latest data-related controversy to hit UK police forces this month.

It follows an admission by the Police Service of Northern Ireland (PSNI) that personal data on all its serving members was mistakenly published in response to a freedom of information (FOI) request.

The revelation of the PSNI breach was followed by Norfolk and Suffolk Police’s announcement that the personal data of more than 1,000 people, including crime victims, was included in another FOI response.

South Yorkshire Assistant Chief Constable Rick Alton said: “I am deeply sorry this has occurred and after we became aware of the loss in data, we notified the Information Commissioner’s Office and began work to attempt to recover it.

“We’ve had a team of people working around the clock to manually check each case currently within the criminal justice system.

“We’ve brought in digital forensics specialists to explore how this data loss occurred and to establish if the data can be recovered.”

Mr Alton added: “We will provide an update concerning this when further work has been undertaken. Whilst we remain hopeful, there are no guarantees, so it’s important the victims and the wider public are informed.”

South Yorkshire’s Police and Crime Commissioner Alan Billings said: “I have been made aware of a loss of data from the force’s storage systems and the work that is taking place to recover the data.

“There may be implications for victims and witnesses and the wider criminal justice system as some of this footage may be evidence in upcoming court cases. The force is working through the implications and direct contact is being made with those affected.”

He added: “This incident is disappointing and concerning and the police need to understand quickly what has happened and why.

“I have been briefed by the Deputy Chief Constable and will continue to receive updates as the work continues to recover the data.

“I will also be seeking a full explanation as to how this incident occurred and what measures will be put in place to prevent it happening again.”