The Mayor is elected by the supplementary vote method for a fixed term of four years, with elections taking place in May. As with most elected posts in the UK, there is a deposit, in this case of £10,000, returnable on the candidate's winning at least 5% of the first-choice votes cast.
In 2004, the second election was held. After being re-admitted to the Labour Party, Ken Livingstone was their official candidate. He won re-election after second preference votes were counted, with Steve Norris again coming second.
The remaining local government functions are performed by the London borough councils. There is some overlap, for example the borough councils are responsible for waste management, but the mayor is required to produce a waste management strategy.
They have also included the London Partnerships Register which was a voluntary scheme without legal force for same-sex couples to register their partnership, and paved the way for the introduction by the United Kingdom Parliament of civil partnerships. Unlike civil partnerships, the London Partnerships Register was open to heterosexual couples who favour a public commitment other than marriage.
As Mayor of London, Ken Livingstone was also a supporter of the London Olympics in 2012, and is known to encourage sport in London; especially when sport can be combined with helping UK charities-like The London Marathon and British 10K charity races. However, Livingstone, in a Mayoral election debate on the BBC's Question Time (TV series) programme in April 2008 did state that the primary reason he supported the Olympic bid was to secure funding for the redevelopment of the East End of London. In the summer of 2007 he brought the Tour de France cycle race to London.
In May 2008, Boris Johnson introduced a new transport safety initiative to put 440 high-visibility police officers on bus hubs and the immediate vicinity. A ban on alcohol on underground, bus, Docklands Light Railway, and tram services and stations across the capital was announced.
Also in May 2008, Boris Johnson announced the closure of The Londoner newspaper, saving approximately £2.9 million. A percentage of this saving will be spent on planting 10,000 new street trees.
In 2010 Boris Johnson extended the coverage of Oyster Card electronic ticketing to all National Rail overground train services 
Also in 2010 Boris Johnson opened the Barclays Cycle Hire scheme with 5,000 bicycles available for hire across London. Although it should be noted that the plans for this were created under Ken Livingstone's administration.
In 2011 Boris Johnson set up the Outer London Fund, a money pot of up to £50 million designed to help facilitate better, more effective local high streets. Areas in London were given the chance to submit proposals for two separate pots of money, which would be granted to them if their bid was successful. Successful bids for Phase 1 included Enfield, Muswell Hill  and Bexley Town Centre. The recipients of Phase 2 funding are still to be announced.
In January 2013 Boris Johnson appointed journalist Andrew Gilligan as the first Cycling Commissioner for London.
In March 2013 Boris Johnson announced £1 billion of investment in infrastructure to make cycling safer in London, including a 15 mile East-West segregated 'Crossrail for bikes'.