(1) The MCA Enforcement Unit (for a merchant shipping offence); or (2) the police (for an alcohol-related offence or any other offence under UK law); or (3) HM Revenue and Customs (HMRC) (for an offence under Customs regulations). The Enforcement Unit liaises with other relevant bodies to determine which will lead in the case. The MAIB does not enforce the law, but will notify the MCA where an offence is discovered in an investigation.