HMRC Fraud Investigation Service (FIS) uses Code of Practice 9 as part of the Contractual Disclosure Facility. Code of Practice 9 outlines HMRC’s approach to suspicious, planned tax evasion and illustrates how to use a contractual disclosure facility. It explains the repercussions of admitting deliberate tax fraud, the procedure after admission, and the benefits of full disclosure to HMRC. HMRC only offers a Contractual Disclosure Facility (CDF) and issues Code of Practice 9 when significant tax fraud is suspected. You should get specialist advice before entering into CFD with HMRC. There may be reasons why HMRC have issued a COP9 letter without any due diligence, and it may be a matter of simple compliance.