The notification system is supposed to allow local European police agencies to monitor people convicted of serious crimes abroad and to prevent offenders from escaping their convictions by moving to another European Union country.

The Guardian quoted from the minutes of a meeting in May of the ACRO Criminal Records Office, a British police unit, indicating officials knew about the problem but did not want to send out alerts belatedly.

“There is a nervousness from Home Office around sending the historical notifications out dating back to 2012 due to the reputational impact this could have,” the minutes say, according to The Guardian, which published its article on Tuesday.

Opposition Labour lawmakers and European lawmakers called for an urgent investigation.

A Home Office spokeswoman said on Tuesday night that “work is already underway with the police to resolve this issue as quickly as possible.” The Home Office said it sent more than 30,000 notifications about convictions to European Union member states last year, and received more than 16,000 from other member states.

The ACRO Criminal Records Office did not immediately respond to requests for comment.

The criminal records office told The Guardian that the problem was a technical one that stemmed in part from cases in which an offender had dual nationality. It said a software fix had been developed that would be released in the next update, though it said it did not know when that would be.