Accountants are legally obliged to report any knowledge or suspicion, or grounds for either. Full definitions can be found in the government’s advice document AML Guidance for the Accountancy Sector
Any employee is legally obliged to report suspicions to their Money Laundering Reporting Officer (MLRO) or deputy MLRO (DMLRO). When that report has been submitted, the employee’s legal responsibility ends, passing to the MLRO who must consider whether to file a Suspicious Activity Report (SAR) to the National Crime Agency (NCA).
Failing to comply with the current money laundering regulations is a criminal offence.