Greater London is often referred to as "the City" or "the Square Mile" and it forms the main financial district. Archaically, the urbanised area of London was known as the Metropolis. In common usage, the terms "London" and "Greater London" are usually used interchangeably. Greater London is officially divided for some purposes, with varying definitions, into Inner London and Outer London. For some strategic planning purposes it is divided into five sub-regions. Greater London is under the strategic local governance of the Greater London Authority (GLA). It consists of an elected assembly, the London Assembly, and an executive head, the Mayor of
Central London "Scheme A" envisaged a central London borough, one of 25, consisting of the City of London, Westminster, Holborn, Finsbury and the inner parts of St Marylebone, St Pancras, Chelsea, Southwark and Lambeth. The boundary deviated from existing lines to include all central London railway stations, the Tower of London and the museums, such that it included small parts of Kensington, Shoreditch, Stepney and Bermondsey. It had an estimated population of 350,000 and occupied . "Scheme B" delineated central London, as one of 7 boroughs, including most of the City of London, the whole of Finsbury and Holborn, most of Westminster