Officials from London's team bidding to host the 2012 Olympic Games are seeking an alliance with rivals Madrid, according to reports.
London wants to secure the Spanish capital's votes should they be knocked out of the contest to host the Games.
The cities face favourites Paris, plus Moscow and New York, in Wednesday's International Olympic Committee vote.
It is said that contact has been made with senior Madrid figures as part of a strategy to capture key votes.
Although no formal deal is in place, it is suggested London would work to return the compliment should they suffer an early exit.
Bid experts believe Moscow and New York will be eliminated in the early rounds when IOC members make their choice in Singapore, leaving a three-way battle between Paris, London and Madrid.
Should Madrid be the next city to be knocked out, the way their votes then go will prove decisive - and the same would apply were London to be eliminated.
Some 100 of the 116 members will vote to begin with.
IOC president Jacques Rogge has decided to sit it out, Bulgarian Ivan Slavkov has been suspended following a BBC investigation and the 14 members from the five nations battling for hosting rights cannot take part until their city is eliminated.
It is understood London's backers have been attempting to woo Juan Antonio Samaranch, the Spanish former IOC president.
He is the man credited with bringing the Games to Barcelona in 1992 and still still wields significant power among a section of IOC members.
His son Juan Antonio Samaranch Jr is a leading executive on the Madrid bid.
London 2012 bid chairman Lord Coe has known Samaranch senior since the 1980s when he was appointed by him to several Olympic commissions.
One senior London backer told the Press Association: "Madrid is the key to this whole contest.
"We know if they get knocked out that they cannot guarantee all their votes - and neither of course can London should we be knocked out - but if someone like Samaranch could then start working on our behalf it could prove decisive."
If Samaranch does throw his weight behind London as a second choice then he might want the favour repaid if his son stands for election as IOC president against Rogge in 2009.
Coe admits to having a "good" relationship with Madrid.
Speaking from the resort of Sentosa near Singapore, where he has been fine-tuning his vote presentation, Coe said: "The former president of the IOC is a close friend.
"His son in the last year or so has also become a good friend.
"But I worked closely with all the bids - we have to know what is happening out there."