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 Units. The MSC has its own internal rank structure. The prefix "Woman" in front of female officers' ranks has been obsolete since 1999. Members of the Criminal Investigation Department (CID) up to and including the rank of Chief Superintendent prefix their ranks with "Detective". Detective ranks are equivalent in rank to their uniform counterparts. Other departments, such as Special Branch and Child Protection, award non-detectives "Branch Detective" status, allowing them to use the "Detective" prefix. None of these detective ranks confer on the holder any extra pay or supervisory authority compared to their uniformed colleagues. The Metropolitan Police Service consists