Prisoners were given more than £1 million in compensation after being released late from jail over the last three years, figures showed today.
The Ministry of Justice paid 280 inmates an average of £3,500 each after they were kept in jail for longer than they should have been.
Prisoners can get £110 for each day they are wrongly kept in, taking the totals for late-release compensation to £276,000 in 2007/08, £491,059 in 2008/09, and £260,000 in 2009/10.
The TaxPayers' Alliance called for the Ministry of Justice to "get its house in order".
"Law-abiding taxpayers will be appalled to learn that they're paying this compensation straight into the pockets of ex-prisoners," a spokeswoman said.
"Detaining convicts is expensive enough without these additional costs.
"The Ministry of Justice should get its house in order to avoid the sort of mix-ups that allow criminals to profit at the expense of the rest of us."
But a Ministry of Justice spokesman said it was open for all prisoners "to pursue civil litigation claims for any perceived wrongdoing".
"Each litigation case is dealt with on its merits and, so far as the evidence allows, all claims are robustly defended," he said.
"In fact the Prison Service defends significantly more civil claims than are settled.
"Such claims are only settled on the basis of strong legal advice from the Prison Service's appointed solicitors and/or barristers.
"The amount of compensation is determined following a full analysis of all the available evidence and taking account of the Judicial Studies Board Guidelines."
He went on: "Taking indefensible cases through to court only results in more expense to the public purse.
"Prisoners may also seek compensation through the internal complaints procedures, without going through the legal process, for items such as lost/damaged property.
"Each claim is investigated and, if substantiated and the prison found to be at fault for the loss/damage, the prisoner may receive compensation."
The figures were released following a request under the Freedom of Information Act.