The mayor of London is the chief executive of the Greater London Authority. The role was created in 2000 after the Greater London devolution referendum in 1998, and was the first directly elected mayor in the United Kingdom.The current mayor is Sadiq Khan, who took office on 9 May 2016. The position was held by Ken Livingstone from the creation of the role on 4 May 2000 until he was defeated in May 2008 by Boris Johnson, who then also served two terms before being succeeded by Khan. The mayor is scrutinised by the London Assembly and, supported by their Mayoral Cabinet, directs the entirety of London, including the City of London (for which there is also the Lord Mayor of the City of London). Each London Borough also has a ceremonial mayor or, in Croydon, Hackney, Lewisham, Newham and Tower Hamlets, an elected mayor.