[3] The Conservative candidate was determined by a primary election open to the entire London electorate, originally scheduled for October 2006.

Candidates who had applied by 4 August deadline included Richard Barnes, London Assembly member for Ealing and Hillingdon, who withdrew in July 2007 and threw his support behind Boris Johnson;[4] Andrew Boff, former Hillingdon and Hackney London Borough Councillor; Nicholas Boles, Policy Exchange think-tank director, who withdrew in July 2007 for health reasons; Dr Robert Frew, a cultural policy and management specialist; Victoria Borwick, Kensington and Chelsea London Borough Councillor; Warwick Lightfoot, also a Kensington and Chelsea councillor; and Lee Rotherham.

[7][8] Prospective applicants who subsequently publicly declared were Lurline Champagnie, a London Borough of Harrow councillor; Winston McKenzie, a former boxer;[9] and disc jockey Mike Read.

[11] Around this point former Conservative Prime Minister Sir John Major was considered a possible candidate, but he turned down an offer from David Cameron.

In January 2008, Bushell stepped aside (due to work commitments) in favour of Fathers-4-Justice campaigner Matt O'Connor, who successfully stood against Andrew Constantine, a City of London Banker, in a selection contest.

In October 2006, UKIP talked of talkSPORT presenter James Whale standing against Ken Livingstone in the 2008 election.

[26] On 12 March 2007 the party selected Siân Berry as its mayoral candidate after a ballot of its London members, receiving 45% of the vote.

[28] In December 2007 former boxer Winston McKenzie told the BBC that he intended to stand for Mayor of London as an independent on an anti-gang crime platform, having failed to secure the Conservative nomination earlier in the year.

[32] The London listings magazine Time Out planned to recruit a self-financing candidate to stand on a manifesto agreed by its readers.

[35] In March 2007 following widespread speculation that John Bird, founder of The Big Issue, would seek the Conservative nomination,[36] he stated that he would stand as an independent, on a platform of "social inclusion".

[37] Chris Prior planned to stand on a platform to abolish the congestion charge[38] for the London Assembly but pulled out of the mayoral race shortly before the close of nominations.

John Flunder was to be the Senior Citizens Party candidate for Mayor of London[40][41] but did not submit a valid nomination.

LondonElectsYou.co.uk, a social networking site aimed at selecting a member of the public to contest the election with a £50,000 campaign budget, was set up in March 2008.

[44] In December 2007 media reports that peace protester Brian Haw would stand for Mayor of London[45][46] remained unsubstantiated.

Labour and the Greens formed a second preference pact, urging Livingstone supporters to give their second choice vote to Berry and vice versa.

[51] The Open Rights Group reports that there was equipment directly connected to the counting servers to which observers had limited or no access and that the presence of error messages, bugs and system freezes indicates poor software quality.