Chief constable is the rank used by the chief police officer of every  territorial police force in the United Kingdom except for the City of London Police and the Metropolitan Police, as well as the chief officers of the three 'special' national police forces, the British Transport Police, Ministry of Defence Police, and Civil Nuclear Constabulary. The title is also held by the chief officers of the principal Crown Dependency police forces, the Isle of Man Constabulary, States of Guernsey Police Service, and States of Jersey Police. The title is also held, ex officio, by the president of the Association of Chief Police Officers under the Police Reform Act 2002. It was also the title of the chief officer of the Royal Parks Constabulary until this agency was disbanded in 2004.