[1] Colour key (for political parties): Labour Conservative Green Independent Current or final office holders of a mayoralty are highlighted in bold.

[3] However, in 2001, Ken Livingstone decided not to offer the role to the Conservatives, claiming it would be disruptive,[2] so Nicky Gavron retained the post.

[2] Nicky Gavron was originally chosen as the Labour candidate for the 2004 London mayoral election but she stepped aside when Ken Livingstone was invited to rejoin the party.

In his first term, Ken Livingstone came under fire for delegating his powers to his chief of staff, Simon Fletcher, rather than the deputy mayor on several occasions.

[7] Sir Simon Milton, a former councillor, served as Deputy Mayor of Policy and Planning and Chief of Staff to Johnson until his death in office in 2011.