The latest information on the number of households benefiting from tax credits, by each parliamentary constituency from 2003 to 2009, is available in the HMRC snapshot publication "Child and Working Tax Credits Statistics. Geographical Analyses", available at:
The same information for 2008-09 is not yet available as awards have not yet been finalised. However, estimates of the number of recipient families with tax credits, based on provisional awards, as at 1 December 2009, are available in the HMRC snapshot publication “Child and Working Tax Credits Statistics. Geographical analyses. December 2009”, at the same internet address.
HMRC do not produce these statistics separately for child tax credit and working tax credit.