The information requested is not available. HM Revenue and Customs (HMRC) code of practice 26 ‘What happens if we've paid you too much tax credit?’ explains the ways the department collect back an overpayment, and is available at:
The information is not available in the format requested. Estimates of the number of families with tax credit awards, including information on overpayments and underpayments by constituency, based on final family circumstances and incomes, for the years 2003-04, 2004-05, 2005-06 and 2006-07 are available in the HMRC publications ‘Child and Working Tax Credits Statistics. Finalised Annual Awards. Supplement on Payments. Geographical Analysis’, for each relevant year. These publications are available on the HMRC website at:
End of year adjustments are not incorrect payments: they are a consequence of the flexible system of tax credits that means that families can get extra support when their needs are greatest.