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 District although within the boundaries of the MPD, are policed by the Metropolitan Police. The Greater London Authority Act 1999 defines the Metropolitan Police District as consisting of "Greater London, excluding the City of London, the Inner Temple and the Middle Temple." The City of London has its own police force, the City of London Police, which also covers the Inner and Middle Temples. As constables of both forces are empowered throughout England and Wales, mutual assistance is a routine matter. The City of London has limited policing jurisdiction with parks constabularies within their lands at Hampstead Heath and Epping Forest