Following a data match with DWP, HMRC discovered that 28 000 families, subsequently revised to 33 000, had not been receiving the disability element of child tax credit. While this might have been going on since 2011, HMRC was only prepared to back date the child element to the April 2016.
CPAG is challenging the refusal to backdate payments further on the basis that the underpayments were caused by official error. The case is currently at the First tier tribunal. A hearing date has not been set.