Boris Johnson
Tory candidate Boris Johnson heads to the polling station to vote. (Reuters)

Boris Johnson has been re-elected mayor of London following a colourful campaign against his antagonist in the 2008 election, Ken Livingstone.

Early indications and an exit poll suggested that the Conservative candidate was on course to win but his victory was confirmed just before midnight on Friday with Johnson securing 1,540,811 votes and Labour's Livingstone 992,273 votes after second preferences were counted.

Livingstone, who preceded Johnson as mayor from 2000-2008, was heavily criticised for using a company to allegedly avoid income tax on his media earnings. The former mayor also came under fire after suggesting that London's Jews would not vote for him due to their relative wealth.

Johnson also had some questionable moments of his own, twice deploying four letter words during the campaign, once on BBC television and once in a lift during angry exchanges with Livingstone. He has also been criticised for the slowness with which he responded to the riots last year.

On policy Johnson has pledged to boost investment in the capital by cutting waste in City Hall, while Livingstone has focused on the issue of cutting travel fares.

Johnson's victory is likely to be the only source of comfort for the Conservative Party which has suffered significant losses in local election results up and down the country to the Labour Party, a fact picked up by Livingstone who cheekily said in his concession speech that Johnson's victory had probably "sealed the next Tory leadership election".