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HMRC internal manual

Claimant Compliance Manual

Discrepancy Examinations and Enquiries: Information: Time limits for Enquiries: 'The Enquiry Window'

There are strict time limits on when an enquiry into someone’s tax credit entitlement can be opened. These time limits are usually referred to as the ‘enquiry window’.

An enquiry cannot be started:

  • before the window has opened, see CCM17130
  • after the window has closed, see CCM17140.Once the enquiry has been started there is no statutory restriction on the length of time it can last, but the claimant has the right to ask us to close the enquiry, see


You can find more detailed guidance regarding the enquiry window at CCM12020. Details of the enquiry windows when there have been multiple awards are at CCM12090 and CCM12095.