Mayor of London

The Mayor of London was the title of the chief administrator of London in England on Earth.

History
Ken Livingstone was the Mayor of London in 2004. That year he was tied up in his office by Martin and an android duplicate of Livingstone was created in his place. The android allowed the Doctor and his companions into Tate Modern and was responsible for the speech at the opening ceremony of the Tomorrow Windows. During the speech, the duplicate's head split in two, revealing an electron bomb that later destroyed Tate Modern. The real Ken Livingstone was later found in his office by the police. (PROSE: The Tomorrow Windows)

A banner for the Mayor of London appeared outside the National Gallery in 2005. (TV: )

Fiona McAndrew was the Mayor of London in 2006. She won the election with over one million votes and served for a year. Her priority when she became mayor was law and order, leading her to accept Yvonne Hartman's offer to build the Law Machines to police the city. She believed that the scheme would greatly boost her approval ratings. Yvonne believed that she was a career politician. (AUDIO: The Law Machines)

A male Mayor of London was reported missing by the Evening Standard in the early 21st century. The Tenth Doctor created a decoy "soup" of the mayor's DNA to prevent time assassins from the 27th century from assassinating the mayor and erasing his lineage, including Lithops, President of Mars. (COMIC: Bus Stop!)

Boris Johnson was the Mayor of London in 2012 during Monos' graffiti attacks on London landmarks. When he gave a statement to BBC News, he promised that the miscreant would be sorry for his actions. (COMIC: Sticks & Stones)

Behind the scenes
Aliens of London seemingly contradicts the audio story The Law Machines, both of them set in 2006, as in Aliens of London a Londoner can be heard 8:06 into the episode blaming Livingstone for the panic in London following a spaceship crashing into the Thames. However, Aliens of London does not directly identify Livingstone as the Mayor, which in the real world he served as from 2000-2008. The DWU also appears to have held mayoral elections at different times to the real world, as Livingstone was re-elected in 2004, a few months before the filming of the the banner seen in the background of Rose.