The cost of dealing with complaints in the Tax Credit Office between 1 November 2006 and 31 October 2007 was around £6.5 million.
It is not possible to provide costs for other areas of HMRC that might also handle complaints relating to tax credits.
(2) what the cost to the Adjudicator's Office of dealing with complaints about tax credits was in the last 12 months.
The Adjudicators Office advise that approximately 39 full-time equivalent staff members dealt with complaints about tax credits in the last 12 months.
The overall costs of the Adjudicator's Office are published in her annual report which is available at:
http://www.adjudicatorsoffice.gov.uk/pdf/report2007.pdf.