Although Conservative candidate Boris Johnson won the Mayoral election, the Assembly election produced the Labour Party's best result since the inception of the London Assembly; this was subsequently surpassed by the party's performance in the 2016 election.

An additional eleven members are allocated by a London wide top-up vote with the proviso that parties must win at least five percent of the vote to qualify for the list seats.

All registered electors (British, Irish, Commonwealth and European Union citizens) living in London who were aged 18 or over on Thursday 3 May 2012 were entitled to vote in the Assembly election.

Those who were temporarily away from London (for example, away working, on holiday, in student accommodation or in hospital) were also entitled to vote in the Assembly election.

[2] The deadline to register to vote in the election was midnight on Wednesday 18 April 2012,[3] though anyone who qualified as an anonymous elector had until midnight on Thursday 26 April 2012 to register.