David Cameron’s fortunes have improved sharply since the summer. But he has been brought down to earth by Kate Moss, the supermodel, who apparently mistook him for a plumber. The encounter between the Conservative leader and Ms Moss took place at a charity function.

Mr Cameron often exudes Etonian poise and confidence, even more so since he succeeded in stopping Gordon Brown calling an early election, but those qualities went missing in the presence of the fashion icon.

Sir Philip Green, the Topshop chief, for whom the model works, asked whether Mr Cameron would like to meet her. The awestruck politician ended up talking to her about flood damage, and she eventually asked him for his phone number so that he could give her advice on drainage.

Mr Cameron tells the story on the ITV1 show Parkinson to be aired tonight, when asked about the “fun” side of his job. “I suppose you get to meet some quite interesting people,” he said. “I went to a charitable dinner the other night and Philip Green came up to me and said, ‘Would you like to meet Kate Moss?’ So I said, ‘Well, of course I’d like to meet Kate Moss’. I went over to her table and on the way over I thought, what on earth am I going to say? And I remembered she actually has a house in my constituency and we’d had these terrible floods in West Oxfordshire and so I said, ‘Very nice to meet you, very sorry about the flooding in your house. I know your local pub has been flooded, I’ve been to see the publican and I know you like to go to the pub and so I know it’s going to reopen in six months’.

“So I went on like this, twittering on, and she turned around and said, ‘God, you sound like a really useful guy, can I have your phone number?’”

Mr Cameron went on: “I went back to my table and said, ‘The good news is, I met Kate Moss and she wanted my telephone number. The bad news is, I think she thinks I’m something to do with drainage’.”

The Tory leader is a guest on Michael Parkinson’s show, with the Formula One star Lewis Hamilton, singer James Blunt and the actor Sir Ian McKellen. Parkinson compared the rivalry between Mr Cameron and the Prime Minister with that between Hamilton and fellow driver Fernando Alonso.

But Mr Cameron, who chatted in friendly fashion with Mr Brown on their way to the Lords for the Queen’s Speech on Tuesday, before they turned on each other in brutal fashion in the House later, was careful not to attack the Prime Minister personally.

“You don’t like him much, do you? He’s your Alonso, really, isn’t he?” the presenter asked. Mr Cameron replied: “It hasn’t got that bad yet. The truth is that I really don’t know him very well. We see each other at official events and we talk a little bit. The truth is, we just don’t agree about big things, about the future of our country and how we should run things . . . we should work together, of course, but where you disagree I don’t think you should hide it.”

Mr Cameron admitted that his CV was “pretty corny – went to Eton, went to the Treasury. I accept it’s not a hard luck story. I went to an amazing school and I had a very privileged upbringing.”

He also spoke about the challenges that he and wife, Samantha, face in bringing up their disabled son, Ivan.

“I don’t think that it has changed me completely as a politician but it has certainly made me think a lot about politics, the health service and things we need to do to help families,” he said.

“We are lucky, though. We are wealthy and we can afford to get extra help. But all of us who are parents of disabled children are not angels – some people are angels and do a fantastic job, but most of us are just normal mums and dads trying to do our best. But it’s a huge struggle and you need a lot of help.” Also onParkinson, Lewis Hamilton admitted that he was moving to Switzerland to avoid a high tax bill. Michael Parkinson asked him: “Well, you say you are going to avoid the photographers and all that, but I will imagine that you have been advised to do so because of the tax also?” Hamilton replied: “That definitely adds to it.”

Parkinson, ITV1 Saturday 10 November, 2007 at 10.35pm

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