The TaxPayers' Alliance has criticised the £500,000 legal aid given to the Connors family from Cheltenham, millionaire travellers convicted for forcing vulnerable men from the MIdlands into slave labour.
The Chief Executive of the campaign group says legal aid should not be made available for the wealthy.
"Handing wealthy criminals huge sums of taxpayers' money is yet another example of why our legal aid system is in dire need of reform," he said.
"Legal aid is important in ensuring access to justice but it must also be sustainable to taxpayers.
"It's incredible that this gang were able to claim so much in the first place, but now that they have been found guilty, taxpayers have every right to expect their money to be reclaimed at the very least."
It's emerged a millionaire travelling family who were convicted for forcing vulnerable men to work for hardly any money in Nottinghamshire, Leicestershire and Gloucestershire, received legal aid totalling nearly £500,000.
The Connors family were found guilty last December after a trial at Bristol Crown Court.
The Legal Services Commission paid out the money. It could claim it back if the Connors are proved to have assets of more than £30,000.
A Legal Services Commission spokesman said:
"We manage costs carefully and legal aid rates are considerably less than those paid to lawyers in privately funded cases.
"Trials can cost a lot of money if they last many weeks, are very complex and have thousands of pages of evidence.
"The law says that anyone facing a Crown Court trial for a serious criminal offence can apply for legal aid to ensure they have a lawyer, but funding is subject to a means test which could require them to pay towards their defence."
A family of millionaire travellers who forced vulnerable men to work for a pittance received nearly £500,000 in legal aid it's emerged.
The Connors family enjoyed top-of-the-range cars and expensive holidays - while the workers lived in squalor on caravan sites in Leicestershire, Nottinghamshire and Cheltenham, getting little or no pay.
William Connors, 52, wife Mary, 48, their sons, John, 29, and James, 20, and son-in-law Miles Connors, 24, were jailed in December last year after being convicted of conspiracy to require a person to perform forced or compulsory labour.
The family bought two caravan sites in Gloucestershire 10 years ago but despite their wealth were able to claim legal aid.
The Legal Services Commission paid a total of $461,363.68 for lawyers to defend the family throughout their trial.
The figures were obtained under a Freedom of Information request.