Criminal records data is not being updated fast enough because of a backlog on the Police National Computer.

Figures obtained by the BBC show some forces are taking more than six months to update information about convictions, far longer than the target of seven days.

This means police, courts, the probation service and the criminal records bureau are relying on out-of-date information.

The Conservative party says the public is being put at risk as a result.

Police Performances

Northumberland: 11 Avon and Somerset: 20 Cambs: 56 Met: 248 Cleveland: 419 *average days taken to process 90% of court results (selection)

When a court makes a sentence, the result is passed on to the relevant police force, which is responsible for inputting it into the Police National Computer.

There are 15 million case records currently on the computer.

The figures obtained by Radio 4's Today programme show the length of time for each force to process 90% of their results.

This varies between 11 days (Northumberland) and 419 days (Cleveland).

'Worrying'

The assistant general secretary of the National Association of Probation Officers, Harry Fletcher, said it was a daily problem reported by his members.

In one case, Mr Fletcher said a man facing 30 domestic violence charges had, according to his computer form, no previous convictions.

It's horrendous for public safety and every member of the public should be concerned about it James Paice MP

In fact, he had been convicted of incest and been on probation for two years.

Mr Fletcher said: "It's very worrying because all of us in the criminal justice system - the police, prisons, the courts themselves and probation - rely on this information.

"If this information is wholly inaccurate, we are all going to make mistakes."

James Paice, the Conservative spokesman on policing, claims the home office tried to prevent the release of the figures.

Today initially tried to obtain the figures last year and was first told they did not exist, then that they were not for public consumption.

Putting court results on the PNC is not the business of the police Ian Reedhead Association of Chief Police Officers

Eventually, they were released after an approach under Freedom of Information procedures.

Mr Paice believes the problem has a major impact on the accuracy of the Criminal Records Bureau, which vets people wanting to work with children.

He said: "It's horrendous for public safety and every member of the public should be concerned about it."

The police have said the situation is improving but the job of inputting the data is not one they should be doing.

Ian Reedhead, of the Association of Chief Police Officers, said: "I would have to say, putting court results on the PNC is not the business of the police."

He added the work was a diversion from fighting crime.