ACPO was composed of the chief police officers of the 44 police forces in England & Wales and Northern Ireland, the Deputy Chief Constable and Assistant Chief Constable of 42 of those forces and the Deputy Commissioner, Assistant Commissioner, Deputy Assistant Commissioner and Commanders of the remaining two - the Metropolitan Police and City of London Police. Certain senior non-police staff and senior members of national police agencies and certain other specialised and non-geographical forces in the UK, the Isle of Man and the Channel Islands were also members.