Paedophiles 'slip through the net to work with children'

The Home Office has been plunged into a fresh crisis by news of the errors dating back at least nine years.

The Home Office has now admitted ministers had been aware of the scandal since last summer but had failed to make any public announcement.

A spokesman denied there had been any cover-up but could not explain why the information was kept secret.

The mistakes involve officials failing to cross-reference Criminal Records Bureau checks with police forces' criminal intelligence databases when deciding whether individuals were safe to work with children.

The blunders centre on the use of "non- sanction detections" (NSDs), where police knew a crime had been committed and identified a suspect but for various reasons no charges were brought.

A massive operation is under way to identify cases where police suspected that an individual was involved in sexual crime, child abduction or violence, but schools and other organisations were not warned.

It is feared that many dangerous offenders may have slipped through the net, leaving huge numbers of children vulnerable to abuse.

So far the Metropolitan Police alone have found 354 cases where background checks failed to spot police suspicions.

Scotland Yard said that "roughly 53 cases could require further information to be shared with employers".

According to official documents seen by the Daily Mail, early studies suggest upwards of 100,000 other cases where incomplete checks were made, and which now need urgent scrutiny.

Poor quality criminal background checks allowed Ian Huntley to get a job as a school caretaker before the Soham murders, and procedures are supposed to have been dramatically improved in the five years since.

The scale of the blunders is a massive blow for the new Home Secretary Jacqui Smith just days after taking up her post.

The potential number of blunders dwarfs the foreign prisoner scandal which erupted last year, and cost her predecessor Charles Clarke his job.

Shadow Home Secretary David Davies has demanded urgent answers from the Home Office, claiming that the department was failing in its central duty to protect the public.

He said: "This is precisely the issue that should have been dealt with by the Bichard inquiry [into the Soham murders] which reported several years ago. This was not done."

The Home Office spokesman said: "This is an operational matter for the Metropolitan Police.

"Ministers were made aware of the issue in summer 2006 and immediately instructed the Association of Chief Police Officers (ACPO) to review the use of nonsanction detections nationally.

"The results of the ACPO review revealed no concerns around public protection in any other force.

"The Metropolitan Police Service have given assurances to ministers that work is well in hand to review past checks to ensure whether further information needs to be given to employers with public protection as a top priority."

The Home Office has been beset by a series of high-profile problems which saw former Home Secretary John Reid declare it was "not fit for purpose".

More than 1,000 foreign criminals were released from prison without being considered for deportation.

It also emerged that 27,500 criminal convictions given to Britons overseas had not been entered on the police computer.

The latest blunder has echoes of mistakes by police in Cambridgeshire and Humberside which led to Ian Huntley, who also used the alias Nixon, getting the all-clear to work with children.

A mix-up over Huntley's name failed to reveal that he had been charged with rape, and had been investigated over a further three rape allegations, four reports of having sex with a minor and one alleged indecent assault on an 11-year-old.