An estimate of the number of lone parents claiming tax credits is published in the HMRC publication “Child and Working Tax Credit Statistics. Finalised Annual Awards 2005-06”. A provisional estimate is also published in the “Child and Working Tax Credit Statistics. April 2007”. Both publications are available on the HMRC website at:
http://www.hmrc.gov.uk/stats/personal-tax-credits/cwtc-quarterly-stats.htm