General principles: HMRC enquiries and compliance checks
A wide range of possible triggers such as random selection, risk‑based profiling, return errors or omissions, late filing, large or unusual claims, third‑party data, data‑matching systems, and past compliance history tends to cause HM Revenue and Customs (HMRC) in the United Kingdom to open either:
– a formal enquiry into a tax return; or
– a broader compliance check into a person’s tax position