Could Hamilton join Red Bull?
As Lewis Hamilton ponders the fall-out from his controversial performance in Canada, he has more on his mind than a few lost points in the world championship.
Formula 1's most exciting driver is pondering his future as he watches Red Bull's Sebastian Vettel canter to a second consecutive world title.
As Mark Hughes explained in his column, Hamilton's frustration is down to the fact that he believes he is the fastest driver in the world, that he would beat any of his rivals if they were all driving the same car. It is a belief largely shared within Formula 1.
Most would probably say Fernando Alonso was the best driver - by which they mean the most complete - but they would agree that Hamilton is certainly the quickest. Although Vettel is gaining increasing support in both categories.
For Hamilton, it is proving increasingly hard to cope with the fact that he has won the world title just once, in 2008, and that he is facing a third consecutive year in a car that is arguably not really fast enough to allow him to compete for another.
McLaren's race pace - far superior to its qualifying speed - is clouding the issue slightly, but it's hard to argue with Vettel's five wins and two second places in seven races.
Given these circumstances, it is easy to see why the 26-year-old Englishman might be beginning to wonder whether McLaren is the team to satisfy his burning ambitions.
Not for the first time, the concept of Hamilton joining Red Bull raised its head again in Montreal - and that was even before Autosport revealed on Monday that he had spent 15 minutes in a private meeting with Red Bull team boss Christian Horner on Saturday evening at the Circuit Gilles Villeneuve.
According to Autosport, the meeting was described by a Red Bull "source" as a "social visit". That "source" may or may not be Horner himself.
Hamilton has played down the idea of leaving McLaren, saying the team have a car capable of winning races and that there is no reason to leave while they remain competitive. He also says it is not unusual for him to talk to rival team bosses.
But that is not an outright denial, so the issue of his future will continue to remain a source of speculation.
Could the meeting with Horner be the start of serious negotiations about a move to Red Bull? Certain sections of the media suggest it is wrong to attach too much significance to Saturday's chat, claiming it would be foolish for a driver to walk over to a rival team's HQ in full view of the F1 paddock with the express intention of discussing his future.
But people have either got short memories or do not pay close enough attention.
When Alonso joined McLaren for 2007, it was the culmination of a process that began in 2005. Ron Dennis, who was the team boss of McLaren at the time, mooted the idea to the Spaniard in a chance conversation as both men waited to go out on to the podium at the Brazilian Grand Prix, Alonso having just won his first world title for Renault.
Likewise, in Belgium in 2007, with his relationship with McLaren in pieces, Alonso strolled over to the Red Bull motorhome, where he discussed the chances of joining the team with Horner as they sat on the open top deck. I know, because I watched them from the upper level of the paddock.
And so the 2011 F1 driver market 'silly season' starts in earnest.
Alonso has just signed up with Ferrari until 2016, the double world champion is not going anywhere. The same goes for Vettel, who is under contract to Red Bull until 2014. So, of F1's big three, that leaves Hamilton.
Theoretically, he is contracted to McLaren until next year, the result of a five-year deal that was signed in the wake of his stunning debut season alongside Alonso in 2007.
That has always been assumed to be a firm five-year contract, which means any move Hamilton makes - to Red Bull, for example - would have to wait until 2013.
However, it would be very unusual for a driver to sign away his future to a team for that length of time without any opt-out clauses, even if - as in the case of Hamilton and McLaren - that team had groomed him for success since he was 11 years old.
And even if the contract is solid, it does not mean Hamilton cannot move. As one veteran driver manager said: "I don't know the details of Hamilton's contract but if the team-driver relationship gets to an irreconcilable point then it won't matter what the contract says."
So a Hamilton move to Red Bull for next year cannot be ruled out, especially in light of the mixed messages coming out of Red Bull about the future of Mark Webber.
On Thursday, Horner said Webber had made it clear he would like to drive for the team next year, adding that he felt the Australian still had the "motivation and desire" and that Red Bull were "very happy with him in the team".
But 24 hours later, Webber did not sound so sure. "We'll see how we go," he said. "There's a bit to go yet in the summer. Keep thinking."
So what is going on?
Horner shrugged his shoulders when I asked why Webber would say that if he had told him he wanted to continue. But when I explained the situation to a man with long experience of the driver market, he said: "I think you can read that as Horner trying to tease another driver out, getting him to make up his mind."
Could that driver be Hamilton? Is it a coincidence that the Englishman went to speak to Horner two days after the Red Bull boss made those comments to the media?
On the face of it, you might wonder why Red Bull would want Hamilton. They already have Vettel. Putting Hamilton alongside the German would be a wonderful proposition for F1's audience but it would be a massive headache for those inside the team. And such a move would be guaranteed to infuriate Vettel, the company's blue-eyed boy wonder.
But from a global marketing perspective, what could be better? Red Bull have long made a point of letting their drivers race. What better scenario for a company wishing to project an exciting, dynamic, youthful image, than two of F1's three most exciting drivers going at it head-to-head in the same team?
It would be a tricky situation for Horner to handle, as he has already admitted himself, but why would that be a concern for Red Bull founder Dietrich Mateschitz?
Equally, while Vettel would probably be furious at having Hamilton alongside him to start with, he might well come round to the idea. He already has an advantage as the incumbent and, while he may not be as fast as Hamilton, he is, by reputation, better at working with his engineers to get the best out of his car.
If Hamilton did go to Red Bull, it would be in place of Webber. The Australian will not be drawn on the apparent disconnect between his words in Montreal and Horner's but many believe he will leave the team at the end of the year - either into retirement or to another team for one last hurrah.
That team could be Ferrari, where Felipe Massa's future is in question. The Brazilian has a contract for 2012 but he is an inconsistent performer. He is pretty close to Alonso at some races but nowhere near at others.
Massa, I'm told, will keep his seat if he puts in a strong showing at the next race, the European Grand Prix at Valencia on 26 June. If not, Webber is one of the drivers on Ferrari's list of candidates.
Ferrari are, I understand, also interested in Jenson Button and have had some contact with him. When Button joined McLaren in 2010, it was said that he had a three-year contract. But I am told he is a free agent at the end of this year if he wants to be. The prospect - however slim - of losing both his drivers must be giving McLaren team boss Martin Whitmarsh sleepless nights.
Ferrari are also interested in Nico Rosberg, who has impressed since joining Michael Schumacher at Mercedes last year. However, the rumours are Rosberg has been offered a big pay packet to stick with the German team.
That is not surprising given the uncertain form of Schumacher, whose excellent performance in Montreal will not bury memories of less convincing races elsewhere.
Schumacher is on a three-year deal but will he continue beyond 2011 if he cannot retain the speed he showed in Canada? If he doesn't, Paul di Resta, who has impressed enormously in his debut season with Force India, must be a strong candidate to replace him, as a Mercedes protégé.
How many of these prospective moves actually happen remains to be seen but it certainly promises to be an interesting summer.