Jenson Button (r) challenged Lewis Hamilton to a triathlon race

Lewis Hamilton's father Anthony has vetoed a charity challenge between his son and Jenson Button, urging him to concentrate on his title challenge.

Button and Hamilton had agreed to compete against each other in a triathlon to prove who was the fitter driver and raise money for charity.

But Hamilton Sr quickly withdrew his son from the contest.

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

Lewis accepted the challenge like the good sport he is Anthony Hamilton

Button, who recently completed a triathlon in Windsor, offered to donate �10,000 to charity if Hamilton beat him in a triathlon in Bath on 27 July, after Hamilton claimed this week that he was the fittest driver in the paddock and was willing to prove it.

After some good-natured banter between the two, Hamilton accepted Button's challenge - "Let's do it. It's a date," he said - only for his father to veto the idea within half an hour.

Hamilton Sr added: "Lewis accepted the challenge like the good sport he is and in the spirit with which he accepts things.

"But unfortunately for Lewis we are withdrawing him from this."

Meanwhile, Button has laughed off suggestions that tax-exile drivers might be asked to hand over 15% of their income in order to compete.

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Recently, the governing International Automobile Federation (FIA) suggested that system might be replaced with a flat rate, but added that drivers living in tax havens could face a bigger charge.

Super-licences are required by drivers to compete in Formula One and Button, who lives in Monaco, says that any plan to change the system is a non-starter.

He said: "What's the super-licence got to do with where we live?

"A super-licence is to show we're capable of driving in Formula One...it's a licence to go racing, the same as a road licence.

"Where you live hasn't got anything to do with your racing licence."

Fellow Formula One driver and long-time Monaco resident David Coulthard added: "I think you people have got to understand the taxation system.

"Even if you?re a non-resident in the UK, we still pay a percentage of our salaries to race at the British Grand Prix, so my contribution to the UK tax system is still considerably more than any of my family members who have got good jobs and who look after themselves. And I don?t use all the facilities in the UK.

"I had this years ago, when I moved to Monaco, people making comments when they don?t know what the real situation is.

"Our lifestyle choice is a lifestyle choice ? everyone?s free to make that - and I think it?s wrong of people to have a dig at someone else who?s having perceived financial success and choosing to live in a country that suits his needs at that time."