The 2000 London mayoral election was held on 4 May 2000 to elect the Mayor of London. It was the first election to the office established that year; the idea of a mayor of a Greater London Authority (GLA) had been included in Labour's 1997 election manifesto, and after their election a referendum in London was scheduled for May 1998, in which there was a 72% yes vote with a 34% turnout.

The 2004 election to the post of Mayor of London took place on 10 June 2004. It was being held on the same day as other local elections and the UK part of the 2004 European Parliament elections, so Londoners had a total of five votes on three ballot papers. Polling opened at 07:00 local time, and closed at 22:00. See: 2004 UK elections. The Supplementary Vote system was used.