Thousands of criminals are attempting to evade detection by removing electronic tagging devices despite government promises to tighten its monitoring of offenders in the community, an EDP investigation has revealed.

Thousands of criminals are attempting to evade detection by removing electronic tagging devices despite government promises to tighten its monitoring of offenders in the community, an EDP investigation has revealed.

New figures released by the National Offender Management Service show the number of “tag tampers” has tripled over the past year.

The sharp increase comes as growing numbers of lawbreakers are given electronically monitored curfews as governors are asked to consider more inmates for early release with the nation's prison population at crisis point.

The revelation is a further embarrassment to the government's £100m Home Detention Curfew scheme which is overseen by Norwich-based Serco in East Anglia and many other parts of the UK. As well as monitoring those released early from prison the system is also used to track terrorist suspects.

North Norfolk MP Norman Lamb described the situation as disturbing at a time when the justice system is becoming more dependent on community punishments.

He said: “There does not appear to be any real explanation for this increase as it is not in proportion with the increase in those wearing tags. The moment a tag is removed the whole system breaks down and by the time it is detected a crime may already have been committed. This is sure to undermine public confidence.”

Last year more than 4,200 cases of convicts interfering with their tags were recorded compared to just 1,700 in the previous year, according to data released under the Freedom of Information Act. Over the same period the number of people on curfew orders has increased from 30,787 offenders to 38,583. In some cases cigarette lighters are used to burn the band attaching the device to their leg.

In Norfolk, Suffolk and Cambridgeshire 95 tampering cases were recorded - a 17pc increase. The government does not keep a separate record of the number of cases in which tags were successfully removed.

Mr Lamb added: “I am concerned that the government does not appear to be properly monitoring those successfully removing their tags, only attempting to remove them, and I would hope something is done to rectify this.”

Last night Serco spokesman Mike Clarke could not explain the increase but insisted he was confident that all attempts to remove tags were being detected as the devices are fitted with automatic warning systems and are inspected visually on a regular basis.

Offenders who breach their licence are prosecuted by Serco or by the probation service depending on the conditions of their sentence.

“We have procedures in place to prosecute those who tamper with their tags. However, we do not prosecute 100pc of cases because in some instances there are technical breaches which result in a warning letter,” Mr Clarke added.

Leanne Boast, spokesman for the Norfolk probation area, said the region has a good track record of prosecuting any breaches detected. Its target is to initiate breach proceedings within 10 days in 90pc of cases, so far this year this has been achieved in 98pc of cases.

“Norfolk is continually improving its timely enforcement of offenders who do not comply with their orders,” she added. “If offenders remove or tamper with their tags, they can expect to be swiftly brought back in front of a judge or magistrate to face justice.”

Earlier this year the Ministry of Justice promised a change in procedures after a BBC investigation at Serco's headquarters on the city's airport industrial estate found the system suffers frequent crashes and is rendered useless when some offenders take a bath giving them an excuse for avoiding detection.

High profile cases include that of sex offender William Knowles who last year absconded from a bail hostel after cutting off his tag and leaving it in a children's park.

Elizabeth Powell, chairman of the bench at Norwich Magistrates' Court, said the court was determined to stamp down on any breaches. She added: “We deal with these cases robustly as we would with any breach of an order made by the court. We look at aggravating and mitigating factors and obviously if the tag has been broken, this would be an aggravating factor.”

Last year the EDP reported similar Home Office figures showing that thousands of criminals were tampering with their tags, only for officials to backtrack saying the figures were flawed and in fact no records were kept.

The Open Government Unit took 80 working days - 60 more than the statutory limit - to release the information as it considered whether the issue was in the public interest. It refused to release details of communications between the government and Serco about ways in which the system could be improved.