A computer glitch resulted in the UK failing to pass on the details of an estimated 75,000 convictions of foreign criminals to their home EU countries, it has been revealed.
The police national computer (PNC) error is thought to have gone undetected for five years, according to The Guardian.
The PNC is used to share information on investigations by UK law enforcement bodies and can link up with European systems.
As a result of the glitch, authorities in EU countries were not informed about crimes committed by their nationals, told about any risks convicted criminals could pose to the public or the sentences they were given by UK courts.
The PNC produces daily updates about foreign offenders.
These are then sent on to European bodies by the ACRO Criminal Records Office.
A spokesman for the ACRO - a national police unit which organises information and shares police data internationally - said the figure was estimated to be approximately 75,000.
They said the unit relies on PNC files to send notifications to other countries concerning cases where one of the nationals had been convicted in a UK court.
In a statement, the ACRO said: "Work is under way with the Home Office to resolve the issue as quickly as possible.
"A software script has been developed at Hendon, the PNC headquarters, and is due to be released in the next software update."
According to The Guardian's report, the Home Office expressed concerns that the mistake could have caused reputational damage.
It quoted minutes said to be from an ACRO meeting last year which said: "There is a nervousness from the Home Office around sending the historical notifications out dating back to 2012 due to the reputational impact this could have."
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An ACRO spokesman refused to confirm whether or not such comments had been made.
The Home Office said efforts were "already under way" with the police to fix the issue "as quickly as possible".
"Last year, the UK sent over 30,000 conviction notifications through ECRIS to EU member states and received over 16,000 from the EU, helping ensure serious criminals were brought to justice," a spokesperson said.
Data sharing arrangements are expected to be a key consideration in the ongoing Brexit negotiations, with fears a reduction in access to databases could hamper efforts to catch criminals.