Boris Johnson has won a second term as London mayor, beating Labour rival Ken Livingstone by 3%, after a far closer contest than expected, BBC News reports.

Johnson won on second preference votes after failing to gain more than 50% in the first round.

Johnson gained 44% of first preference votes, to Ken Livingstone's 40.3%. After second preferences came into play, Johnson gained a total of 1,054,811 votes, or 51.5%, to the Labor candidate's 48.5% - making it an even closer contest than in 2008.

In his victory speech, Johnson vowed to fight for a "good deal for Londoners from the government that will help us deliver prosperity for everybody in this city".

And he added: "I will dedicate myself to making sure that Londoners and above all, young Londoners, are ready to take the jobs that this amazing city creates."