Understanding COP9 and Why Expats Often Face It The Nature of a COP9 Investigation for Expats When HMRC suspects serious tax fraud or deliberate evasion, they issue a COP9 notice under their Code of Practice 9. This isn't a routine check—it's targeted at behaviour they view as dishonest, offering a civil route via the Contractual Disclosure Facility (CDF) to avoid criminal prosecution in...