London beat favourites Paris for the right to stage the 2012 Games in one of the closest votes in Olympic history on Wednesday.
London beat Paris by just four votes in the fourth and final round of voting, winning 54-50.
It was the closest result since Sydney beat Beijing by two votes in Monaco for the hosting of the 2000 Summer Olympics.
Despite starting as expected front-runner, Paris was never able to get its nose in front in the ballot.
London led at every round except the second when Madrid went briefly in front.
The three other candidates in the opening rounds, Moscow, New York and Madrid fell out one by one in a system under which the lowest ranked candidate is eliminated in each round.
The opening round was remarkably close. London led by 22 votes to 21 for Paris, 20 to Madrid and 19 to New York. Moscow, who picked up 15, went out even though it was just seven off the front-runner.
Madrid picked up most of the Moscow votes in the second round and led with 32 to 27 for London. Paris gained 25 and New York were eliminated with 16.
The votes for the US city then went largely to London who went back into the lead with 39. Paris were second with 33, leaving Madrid eliminated on 31.
Paris closed the gap in the final showdown but London held off its rival to win by 54 to 50.