Home Secretary David Blunkett has defended his call for hundreds more prisoners to be released early under the electronic tagging scheme.

Mr Blunkett is due to tell prison governors they should regard "home detention curfews" as the first option for prisoners serving short sentences of three to 12 months.

He said the struggling Prison Service can no longer cope with the increase in its inmate population.

The prison population is at a record level of more than 70,000, but the Home Office insists the impetus for early release is to cut re-offending - not to ease over-crowding.

'Unprecedented'

Mr Blunkett said he had "never experienced anything like" the numbers of inmates, which rose by 4,000 in the first two months of this year.

	Tagging First tested in 1999 Re-offending rates are low Tagging saves over �20,000 a year per prisoner See also: An alternative to prison?

But the Conservatives say the release scheme would "undermine the fundamental principles of justice".

Mr Blunkett will make the early release announcement at the Prisons and Probation Inspectorates conference in London on Thursday

It will lead to hundreds of offenders, including people convicted of burglary and drug offences, being let out up to two months before their sentence is completed.

Mr Blunkett said that despite a rise in the number of prison places over the past five years, the system was still "miles off" being able to meet the demand.

"There has been a 75% increase in the prison population since the mid-1990s," he told BBC Radio 4's Today programme.

"The demand is a 4,000 increase in the prison population in the first two months of this year.

Blunkett says the tagging scheme cuts reoffending

"We have never experienced anything like it and I have to get a grip of it.

"I have to make decisions that both catch the criminals, punish them appropriately, stop them re-offending and have a prison service that has some chance of rehabilitation if they are not going to continue to re-offend."

Mr Blunkett insisted that the move towards early release did not represent a U-turn and said it was consistent with the government's policy of dealing with less serious offenders in the community.

Curfews

He said that the reoffending rate among offenders while they were electronically tagged was just 2% compared to an overall rate of 56% for prisoners.

Offenders with a history of sexual and violent crime will continue to be excluded from the scheme.

All other prisoners serving between three months and four years are currently eligible for tagging.

Shadow home secretary Oliver Letwin MP said: "When a judge sentences a criminal, it is the responsibility of the home secretary to ensure that the criminal in question can serve the sentence in question."

Letwin accused Blunkett of interference

Former high court judge Sir Michael Davies said Mr Blunkett's remarks were "insensitive and ill-timed" and would only "depress the public and encourage the criminal".

Liberal Democrat home affairs spokesman Simon Hughes said more use of supervision in the community for non-violent, less serious offences was "a sensible response" to prison overcrowding and "a good policy".

The announcement comes on the day a poll for The Guardian suggests alarm over rising street crime is boosting the Tories' popularity.

'Common sense'

The ICM survey of more than 1,000 people suggests Labour's lead has been cut from 17 points to nine in the last month, with law and order fears a key factor.

Home Office figures released last year showed that in the first three years of the tagging scheme, introduced in January 1999, just 893 crimes were committed by the 42,853 prisoners released early - a reoffending rate of 2%.

But there appears to be a reluctance on the part of prison governors to use the home detention curfew as just 25% of those eligible for tagging last year were freed early.

Paul Cavadino, chief executive of crime reduction charity Nacro, described Mr Blunkett's plan as "common sense", because it would relieve the pressure on prisons without endangering the public.

Mr Blunkett's speech follows the promise of tough action on street crime after a top level meeting in Downing Street.