THE chairman of Dorchester Prison's Board of Visitors has slammed the system for failing inmates - saying that 80 per cent of prisoners at the jail reoffend after they finish their sentences.

Peter Gregson says that the number of 'revolving-door' prisoners who are sent back to jail are wasting hundreds of thousands of pounds of taxpayers' money each year, when the money could be better spent on finding ways to stop them reoffending.

His shock figures contrast sharply with the Home Office statistics for all prisoners in England and Wales, which say that only 58 per cent of inmates land back in jail.

Mr Gregson said: "The board is becoming increasingly worried by the large number of repeat offenders they see in prison.

"It seems that the prison system has utterly failed the 80 per cent of revolving-door prisoners in Dorchester who come back time and again, and frequently after only a few months of freedom.

"The board believes that this huge number of repeat offenders shows how ineffective the current regime is in local prisons and that more resources must be put into trying to prevent this."

He added: "This is a terrible indictment of the system. With the cost of accommodating a prisoner in Dorchester Prison for a year now running at £22,500 it is common sense to put more resources into finding ways to prevent ex-prisoners reoffending."

The average cost of keeping a prisoner in an uncrowded jail is £27,090, according to the Home Office, with costs rising to £60,000 per year in high-security wings.

Mr Gregson's comments come after the Howard League for Penal Reform named Dorchester as one of the five most overcrowded jails in the country.

Dorchester Prison governor Steve Holland says that his jail is no worse than any other, but says evidence shows that non-custodial sentences, such as community punishment orders, are shown to be more effective in stopping criminals reoffending.

Mr Holland, who took over at the jail in July, said: "It is very difficult to calculate how many of the prisoners we have here reoffend when they go elsewhere.

"But I would say we are no worse than other places. Our cognitive behaviour courses reduce reoffending to about 30 per cent, which is a bit of an improvement, but many of the prisoners are here for less than six weeks so they don't qualify to join the courses.

"Many people sent to jail lose their homes, jobs and family and evidence shows that community punishments are just as effective, if not more so, than jail terms."