How the voting works

Fifty votes will be enough to secure the hosting of the 2012 Olympic Games when the first ballot is taken today at the International Olympic Committee (IOC) session.

London, Madrid, Moscow, New York and Paris have been scrapping in Singapore over every single vote in the most hotly contested bidding war in Olympic history.

Today, all five candidate cities will be put out of their misery. One will have landed the Games.

Of the 116 members of the International Olympic Committee, only 99 will take part in the secret, electronic ballot in round one.

A vote in favor of a city is cast electronically. In each round, each participating IOC member may vote for only one city.

A simple majority -- in this case 50 -- would be enough to end the race immediately.

If, after the first round of voting, no city obtains the absolute majority of the votes cast, as many rounds are held as necessary for a city to obtain a majority.

The city receiving the least number of votes is eliminated after each round, its name is made public straight away and the vote continues with a further round.

If only two cities remain in contention, the one which polls most votes is elected host city.

IOC members from countries putting forward a candidate cannot participate in the vote while their city remains in contention.

France has three IOC members, Jean-Claude Killy, Henri Serandour and the absent Guy Drut. There are three members from the United States, Anita DeFrantz, James Easton and Robert Ctvrtlik.

Russia also has three -- Vitaly Smirnov, Shamil Tarpischev and Alexander Popov -- as does Britain with Princess Anne, Craig Reedie and Phil Craven.

Spain's two IOC members, the Infanta Dona Pilar de Borbon and Juan Antonio Samaranch Jr, are also unable to vote while Madrid remains in the hunt.

Once a city is eliminated, members from that country are able to vote so the number needed to win selection will increase with each round of voting.

Traditionally, the IOC president does not vote though he would be expected to provide the casting vote in the event of a final tie.

Apart from Drut, one other IOC member is absent from Singapore -- Nikos Filaretos of Greece -- and another, Ivan Slavkov of Bulgaria, is deprived of his voting rights.