A computer failure has resulted in the UK's failure to pass details of an estimated 75,000 convictions of foreign criminals to their EU countries of origin, it was revealed.
The National Police Computer (PNC) error is thought to have not been detected for five years, according to The Guardian.
The PNC is used to share information about investigations by UK law enforcement agencies and can connect to European systems.
As a result of the failure, authorities in EU countries were not informed about the crimes committed by their nationals, informed about the risks that convicted criminals could pose to the public or about the judgments that were handed down by the UK courts.
The PNC produces daily updates on foreign criminals.
These are sent to European bodies by the ACRO Criminal Records Office.
A spokesman for ACRO – a national police unit that organizes intelligence and shares police data internationally – said the figure was estimated at approximately 75,000.
They said the unit had PNC files to send notifications to other countries about cases in which one of the nationals was convicted in a UK court.
In a statement, ACRO said: "Work is underway with Home Office to address the issue as soon as possible.
"A software script was developed at Hendon, the headquarters of PNC, and should be released in the next software update."
According to The Guardian's report, the Home Office expressed concern that the mistake may have damaged its reputation.
The report cited minutes from an ACRO meeting last year that said: "There is a nervousness from the Home Office sending historical notifications since 2012 due to the impact on reputation it could have."
An ACRO spokesman declined to confirm whether or not these comments were made.
The Interior Ministry said efforts are "already underway" with police to resolve the problem "as soon as possible".
"Last year, the United Kingdom sent over 30,000 conviction notifications via ECRIS to EU member states and received over 16,000 from the EU, helping to ensure that serious criminals are brought to justice," a spokesman said.
Data sharing agreements are expected to be an important consideration in the ongoing Brexit negotiations, fearing that reduced access to databases may hamper efforts to capture criminals.