LONDON, Sept 17 (Reuters) - Formula One heads for the bright lights of Singapore this weekend with the rumour mill sparking as it spins but the driver merry-go-round seemingly stalled until Lewis Hamilton makes his mind up about his future.
McLaren's 2008 world champion is not alone in holding a key to the carousel but, out of contract at the end of the season, he stands out as a driver with control over his destiny and a man whose talents are both sought and fought over.
If he decides to leave 'home' and move to Mercedes, the 27-year-old Briton will trigger a chain reaction around the paddock that looks sure to coincide with Michael Schumacher's second retirement.
What happens at Ferrari, the other big Formula One conundrum of the moment, will be a decision taken by the Italian team rather than Brazilian Felipe Massa - who wants to stay alongside championship leader Fernando Alonso but risks being ushered to the door.
Yet Ferrari may also have to wait for Hamilton, with potential alternatives to Massa maybe wondering whether a McLaren drive might be a better option than being Alonso's number two.
Hamilton told reporters at the weekend that he was focusing solely on winning a second title with McLaren and would not be distracted by the contract speculation and 'rubbish' swirling around him.
One simple way to end the talk would be to announce a decision, and McLaren have planned further talks with his management between Monza and Singapore.
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There could be a sudden agreement but equally, with both sides seemingly determined to play hardball, there is a risk of relations between him and his current team rapidly deteriorating.
Sooner or later, he will have to decide who offers him the best chance of winning races and titles as well as the most money both in terms of wages and the commercial freedom to create and sell himself as a 'brand'.
Past performance is no guarantee of future success, as any investor in stocks knows only too well, but McLaren have the figures to back up their position as well as the odds - British bookmakers William Hill cut theirs on Hamilton staying at McLaren from 17/20 on Friday to 1/2 on Saturday.
Since Hamilton entered Formula One in 2007, groomed by McLaren for the best part of a decade, his current employers have won 32 races to Red Bull's 30 and Ferrari's 27. Mercedes have one sole victory, excluding the eight won by their predecessors Brawn GP.
McLaren will have to pay Mercedes for their engines from next year, however, with an entirely new power plant to be introduced from 2014.
Hamilton's departure would surely mean the end of the road for seven-times world champion Michael Schumacher, whose 91 wins make him the sport's most successful driver, at the age of 43 and after three disappointing comeback years with Mercedes.
Nico Rosberg has a contract for 2013, won in China for Mercedes and team principal Ross Brawn has said he is staying.
Only a few months ago, Schumacher's choice seemed to be between calling it a day or deciding to race on.
It could be that the German has already decided to go, in which case Hamilton's deliberations will change nothing, but it could also turn out that he no longer has a choice.
Schumacher, who has been on the podium just once with Mercedes, told reporters this month to expect no comment until October.
Waiting in the wings are an increasing list of hopefuls who have caught the eye of the media at least and been linked to McLaren, Mercedes and Ferrari.
They include the Force India pair of Paul Di Resta, a German touring car (DTM) champion with Mercedes and now sharing a manager with McLaren's Jenson Button, and Germany's Nico Hulkenberg.
Sauber's Mexican Sergio Perez is another in the spotlight, with three podium finishes for the Swiss team this season as well as being a member of Ferrari's young driver academy.
Ferrari president Luca Di Montezemolo has said Perez needs more experience to race for the Maranello team but that has not stopped him being linked to both them and McLaren.
Caterham's Finnish driver Heikki Kovalainen, a race winner at McLaren and Alonso's team mate at Renault before that, has been touted by others.
The only ones completely sheltered from speculation are champions Red Bull, with double title winner Sebastian Vettel and Australian Mark Webber. They, alone among the top teams, have already locked down their 2013 lineup. (Editing by Ed Osmond)