London: It is the race that has set the athletics world abuzz: the fastest sprinter in history against the greatest distance runner on the planet.

But already experts are questioning whether Usain Bolt may have overreached himself in accepting Mo Farah’s challenge to compete over 600 metres.

Farah, the double Olympic champion over 5,000 and 10,000m, threw down the gauntlet over the weekend when he proposed an intriguing showdown with the Jamaican over either 600 or 800 metres in a one-off race in aid of the athletes’ respective charitable foundations.

“Are you up for that?” Farah urged Bolt. “Come on, you’ve got to do it. Let’s get it on.”

Bolt, the 100m and 200m world record-holder and the only athlete to win back-to-back 100 and 200m titles at successive Olympics, is not the kind of man to duck a challenge and responded: “That sounds fun. It’s going to be hard but it’s charity, so it’s all about fun and enjoyment. I’m up for anything. Anything’s possible.”

Although he ruled taking on Farah over any distance further than 600 metres, Bolt appeared comfortable with the idea of racing over 1½ laps.

“Six hundred for sure I can try because I’ve done 600 metres in training,” he said.

But former athletes from both sprint and endurance backgrounds believe Bolt could be setting himself up for a world of lactic-induced pain by believing he can keep up with Farah, who appears to have found an altogether different gear this season.

Not only did Farah obliterate Steve Cram’s 28-year-old 1500m record in Monaco earlier this month but he also ran an astonishing 50.89sec final lap at the end of a 5,000m in Gateshead in June.

David Moorcroft, the former 5,000m world record-holder, said his money would be on Bolt over 500 metres but an extra 100 metres would make all the difference to the Londoner.

“I’d go Mo, particularly if he goes for it the whole way,” said Moorcroft.

“Clearly Bolt would be on his shoulder at 400 and might also be on his shoulder at 500 but I think Mo would have enough to win.”

The big question is, will the race actually get off the ground?

Four years ago Ethiopian distance-running great Kenenisa Bekele threw down a similar challenge to Bolt to race him over 600 or 800 metres. Bolt’s reaction was initially positive but the race never materialised.

The difference this time is that both Farah and Bolt share the same manager, London-based Ricky Simms, though when asked on Monday about a possible showdown, Simms said: “I think it’s just a joke. Have you ever seen Usain running 600 metres?

'I think the focus now is on the World Championships in Moscow and then we’ll see what happens after that.”