Friday 4 July at 09:29 : Lewis Hamilton accepted and then quickly retracted a challenge to go head-to-head with British F1 rival Jenson Button in a triathlon event.

Hamilton, the 23-year-old McLaren driver, said earlier this week he believes he is fitter than Button, despite the Honda driver's affection for competing in triathlons.

"So if someone wants to get us going up against each other I'd look forward to it," he had said.

When Hamilton and Button, 28, both appeared in a Silverstone press conference on Thursday, Button challenged his countryman to go through with a contest.

He was even armed with a date -- his next triathlon, in Bath (UK) on July 27. "What if I say 10,000 pounds to the charity of your choice if you beat me? What do you think?" Button said.

"I'm not putting myself into it ... I don't know, I'll probably be working or doing something else. We'll see, we'll see," Hamilton replied to Button, as he got on his mobile phone to check his calendar with an assistant.

Eventually, egged on by F1 veteran David Coulthard, Hamilton agreed -- until 30 minutes later, when his father and manager Anthony issued a media statement.

"Unfortunately for Lewis, we are withdrawing him from this," Hamilton Snr said.

"We are in the middle of a championship and that is the focus of our attention."