According to the National Audit Office's report, if it comes into effect following a no-deal, Operation Yellowhammer will involve coordinating the activities of a number of public bodies across the UK, potentially including:
more than 30 central government bodies, including almost all central government departments;
42 local resilience forums in England and Wales, and equivalent bodies in Scotland and Northern Ireland, which in turn will coordinate the work of local bodies, including police and local authorities;
the Scottish and Welsh governments;
the Northern Ireland Civil Service;
Crown Dependencies, Overseas Territories (including Gibraltar) and Sovereign Base Areas in Cyprus; and,
sectors and industries which are impacted.