A major investigation has been launched by the Home Office after faulty mobile phone data is believed to have been used as evidence in criminal cases for over a year, the Evening Standard can reveal.
There are fears convictions could be challenged and upcoming trials delayed after O2 informed police chiefs that there were concerns about the accuracy of information it was providing to forces.
The problem is understood to date back to mid-2022 and has still not been rectified.
O2, Britain's second largest telecommunications provider, said it was working to fix the matter as "a top priority" and the National Police Chiefs Council (NPCC) has sent out letters warning forces about the unreliable data.
The bug relates to a phone’s unique International Mobile Equipment Identity (IMEI) number and could mean information presented to juries about calls a defendant made or received are incorrect.
It could also impact location data, which is used to pinpoint where an accused person was when a crime was committed.
A Home Office spokesman said: “We are aware of an issue involving a telecommunications operator which has affected the provision of communications data. We are working with the relevant organisations and it would be inappropriate to comment further on this matter while an investigation is ongoing.”
An IMEI number is a phone’s unique identifier and can be used by police to track a handset even if the SIM card has been removed and swapped.
The records provided by mobile companies are often presented in criminal trials but can be particularly relevant in drug dealing and organised crime cases.
Problems with cell site location data discovered in Denmark in 2019 resulted in more than 30 people being released from custody and over 10,000 cases being reviewed by the country.
Danish authorities also postponed dozens of cases under a two-month moratorium on the use of mobile phone records in court, which was imposed after officers found multiple glitches in the software that converts raw data from phone masts into evidence.
The Home Office told the Standard that the case in Denmark was a systemic issue within the police systems itself, rather than with an individual phone provider.
It added that the British police use "multiple avenues" to obtain the required information to seek a prosecution.
Conservative MP Tim Loughton, said he would be raising the issue with the Home Affairs Select Committee on Tuesday.
"This is very worrying," he told the Standard.
"I will certainly be raising this with the Home Affairs Select Committee to see if there is anything we should be doing, or can do.
“The worrying thing then is that we just don't know the extent of the problem.
“We need to have an interim report from the Home Office just to say how big this is, or actually, is it not a bigger problem, but they're doing checks to make sure that it's limited.
“At the moment there's no idea of the scale of this problem, but if it is wide reaching that has potentially very worrying consequences for the security of various convictions."
The Government said it cannot speculate on how many trials this could impact while an investigation is ongoing.
It comes as UK crown courts battle a record 65,000 case backlog, with suspects and victims routinely having to wait up to four years before their cases are heard in court.
The Home Office refused to comment on whether the potentially faulty data was still being included in evidence bundles for upcoming trials.
An O2 spokesman said: “We are investigating an issue relating to the accuracy of some data provided to certain operational partners. We take this matter very seriously and we have notified the relevant bodies, taken steps to help mitigate against a recurrence in the short-term and our teams are currently working to determine the facts and fully resolve any issues as a top priority.”
A spokesman for the NPCC said: “We have been made aware of an error involving some data supplied by a telecommunications company.
“We are working with a range of partners to establish the exact implications of this fault and to ensure appropriate steps are taken to mitigate and resolve the issue.
“A more detailed update will be provided in due course.”
