Is Boris using Olympics as the springboard to No 10?
On Sunday night, the world will be watching as Usain Bolt and Johan Blake line up in the Olympic men's 100m final. British interest will be scant, but it's still the showpiece event of London 2012.
In the meantime, though it may require a Phillips Idowu-style leap, let's turn to another rivalry between two ambitious types who publicly maintain a friendship.
Yesterday, we learned that Boris Johnson is the man Tory supporters most want to see take over as Prime Minister.
A poll by the ConservativeHome website found 32% in favour of the mayor - well ahead of Foreign Secretary William Hague in second place. Chancellor George Osborne, still down in the dumps after his Budget U-turns, was last.
Johnson chose to mark this show of support in typical fashion, writing about "semi naked women" (the female beach volleyball players at Horse Guards Parade), who were "glistening like wet otters".
There is probably only one politician who could write that without being castigated and it is the Mayor of London.
He has cultivated the prized public image of a lovable buffoon, whose 'gaffes' make him even more popular with his supporters.
At the other end of the spectrum, witness the disastrous Aidan Burley, he of the Nazi-themed stag party, whose tweet about the opening ceremony ("multicultural crap") was yesterday branded "idiotic" by the Prime Minister. I don't think we'll be seeing him in line for promotion anytime soon.
Boris slips up, too - sometimes literally, like when he tumbled hilariously into a river during a litter-picking photo shoot. Was it an accident, or part of his carefully-crafted public image?
Speculation about his ambition for No 10 refuses to die, although he has said he's "more likely to be re-incarnated as an olive".
His profile has grown further as the world tunes in to watch London host the Olympics.
Tim Montgomerie, the editor of ConservativeHome, said Boris's popularity is down to his enthusiasm for life: "They like him because he likes them," he says.
In truth, the chances of him succeeding Cameron anytime soon are probably on a par with Britain topping the medals table on the last night of the Games.
Cameron still polls ahead of Ed Miliband as the public's preferred prime minister and Boris would have to resign from City Hall and find himself a parliamentary seat before he could begin to mount a leadership bid. Nonetheless, simply because of his popularity with grassroots Tories, he remains a threat to his fellow Old Etonian, who he insists on referring to as "Dave".
It's by no means as exciting as Bolt-v-Blake. But this rivalry could last a lot longer.