Tax credit overpayments can either be recovered automatically from continuing entitlement or, where entitlement has ended in respect of the overpaid award, HMRC will oversee the direct recovery of tax credits debt.
The overall cost of recovering overpayments of tax credits is not available and could be provided only at disproportionate cost.
I refer to the answer I gave to my right hon. Friend the Member for Birkenhead (Mr. Field) on 26 November 2007, Official Report, column 71W.