PRISONERS released early under a government scheme to cut jail overcrowding have been paid more than £5m in “compensation” for losing free board and lodging.

The figures — disclosed by Jack Straw, the justice secretary, after Tory pressure – have prompted a political row.

Introduced two days after Gordon Brown became prime minister in June 2007, the so-called “end-of-custody licence” (ECL) has allowed nearly 50,000 criminals to walk out of jail early simply because there are too few cells.

Under the scheme those serving between four weeks and four years in jail are released up to 18 days early. Since offenders are automatically released after serving half their sentence, this means they can walk free almost three weeks before the halfway point.

Figures released by Straw show the government has so far paid £5.5m for subsistence to make up for the loss of free board and lodging. Prison governors gave out £2.27m directly, while the Department for Work and Pensions paid them a further £3.11m. Straw said the scheme had cost another £429,000 to administer, making a total cost to the taxpayer of nearly £6m.

Dominic Grieve, the shadow justice secretary, said Straw’s disclosure made a mockery of government criminal justice policy. “Hard-pressed taxpayers will be flabbergasted to learn they are compensating prisoners for being released early – it just adds insult to injury,” Grieve said.

“Money that could have been spent holding and rehabilitating prisoners is being spent on releasing them to reoffend.”

The government has already admitted that prisoners benefiting from the early release scheme have committed almost 1,000 crimes when they would have been locked up.

That figure includes at least three killings which the Tories say would not have happened had ministers built enough prison spaces.

Andrew Mournian murdered his girlfriend Amanda Murphy, a mother of two. He attacked her with his fists on returning to the couple’s home in Dewsbury, West Yorkshire. He had been serving time for a previous attack on her when he was freed early.

Darren Abrams, also a former prisoner, took part in a drunken attack in Portsmouth which led to the death of Jed Sheridan, a 19-year-old student. Abrams hanged himself while on remand. A third fatal incident took place in south Wales last September.

Straw has admitted that the deaths were among 181 alleged violent offences carried out by prisoners released early between June 2007 and last October. The end-of-custody scheme has been dogged by controversy. Last March The Sunday Times revealed that two terrorists had been released early.

David Hanson, the justice minister, said last night:"These payments are made to prisoners who could not otherwise pay for food and accommodation, as they are not able to claim benefits while on ECL. However, sentenced prisoners known to have over £500 in personal funds do not receive any payments.We will end ECL when there is sufficient prison capacity to safely do so.”

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