Tony Blair as the then British Prime Minister summoned up all his persuasive charm and noted negotiating skills to help tip the scales in London's favor despite all the smart money piling on Paris to prevail. Blair, in company with his wife Cherie, turned up in Singapore three days before the vote to embark on an intense round of lobbying to sway floating IOC members. Blair deployed his arm-twisting ability in a frantic 48 hours of pressing the flesh to edge London past Paris by just four votes on the final count.

The battle for 2012 had been so close to call Princess Anne, President of the British Olympics Association, observed before the final vote: "I certainly don't like counting chickens before they have hatched - I have got some chickens and they hardly ever hatch!"

The influence of sending your top guns to back up your bid also paid off handsomely for Sochi, who defeated Pyeongchang and Salzburg for the honor of hosting the 2014 Winter Games at the IOC Congress in Guatemala City in 2007.

Sochi's come-from-behind success was put down in no small measure to the personal intervention of Russian President Vladimir Putin.

Putin had only bothered to address IOC members by video in Singapore in support of Moscow's attempt to secure the 2012 Summer Games.

For the 2014 Winter Games he not only took the trouble to travel to Guatemala but also stunned IOC members by extolling the virtues of Sochi in English - the first time he had addressed an audience publicly in English.

'Captain' Putin - as he was named by the Sochi bid team - and his merry band ensured a relatively comfortable 51 votes to 47 win for Sochi over Pyeongchang.

"The role of the president in our victory should not be underestimated. He did everything and more to make it happen," Putin's press officer Dmitri Peskov said.

Fast forward two years, to Copenhagen next week, and the 'A' List line-up for the four bidding cities is impressive - with one glaring omission:

- Brazil President Luiz Inacio Lula da Silva will be in Denmark hoping to bring home the bacon for Rio.

- Madrid's bid team will have Spanish King Juan Carlos and Queen Sophia, as well as Prime Minister Jose Luis Rodriguez Zapatero fighting their corner.

- Tokyo, the only one of the quartet to have already staged an Olympic Games, hope to have Crown prince Naruhito and Crown princess Masako along with Tokyo's influential Governor Shintaro Ishihara and possibly new Prime Minister Yukio Hatoyama.

- which leaves Chicago.

U.S. President Barack Obama's presence in Copenhagen would be a dream for bid chief Pat Ryan and his 300-strong team - but health issues, not the President's but America's - look set to keep him away.

In his place will be First Lady Michelle Obama, who is due to make a highly personal plea for the Games to come to her home city.

The 2016 race is too tight to call, according to IOC President Jacques Rogge - placing even more emphasis on the last minute presentations accorded to each city to win over IOC members.

Rogge reckons the vote will be as close or closer than in Singapore, but dismissed a notion that President Obama's absence could count against Chicago.

"There is no tradition for all the heads of state to come. We wouldn't see that as being a negative whatsoever.

"They (heads of state) are most welcome but this is not something that we consider as being the most important thing. It is symbolically important. They have an influence by their charisma, but it is not something the IOC is seeking and going after."

Intriguingly though the White House has failed to shut the door entirely on Obama turning up - an advance team travelled to Copenhagen on Monday to make the necessary security preparations should the President's schedule change.