History of the Metropolitan Police Service been headed by a Commissioner, rather than a Chief Constable which is the highest rank in police forces outside London. The first Commissioners to hold the post were Lieutenant-Colonel Sir Charles Rowan and Sir Richard Mayne. When Sir Charles Rowan died, leaving Sir Richard Mayne as the surviving Commissioner, Captain William Hay was drafted in to jointly run the force with Mayne. However, because the two Commissioners did not agree on methods of running the force, since 1855 it was decided that only one Commissioner would run the force. Metropolitan Police patrols took to the streets on 29 September 1829,
Metropolitan Police Service Acts, meaning that they are not police officers. Metropolitan Police officers have legal jurisdiction throughout all of England and Wales, including areas that have their own special police forces, such as the Ministry of Defence, as do all police officers of territorial police forces. Officers also have limited powers in Scotland and Northern Ireland. Within the MPD, the Met will take over the investigation of any serious crime from the British Transport Police and Ministry of Defence Police, if it is deemed appropriate. Terrorist incidents and complex murder enquiries will almost always be investigated by the Met, with the assistance