In Bristol West alone, of the 5,600 tax credit claims 1,800 were overpayments, with the average family paying back £888.89 each.
"These figures are unprecedented and reflect the serious problems not only with the computer system, but inherent within the new tax credit system.
"There are many local cases where the tax credit office has attempted to claw back money that had often been overpaid as a result of internal administrative error rather than customer misinformation.
"Too many families are having their budgets thrown into chaos by the tax credit office causing serious problems and hardship especially for those on low incomes.
"What we do not yet know, however, is how many of these overpayments were a result of official error and how many the Revenue will write off.
"Last week Treasury Ministers signalled changes to the way overpayments are clawed back. The statement was an implicit admission that the Revenue have not been acting responsibly in the past. But new guidance alone will not solve this problem.
"The policy of reassessing income at the end of the award is flawed and a return to a system of fixed awards would end this bureaucratic nightmare for many families."
