With just seven more race before he leaves for Sports Cars, Mark Webber admits that he no longer has the fire in his belly for F1.

Talking to F1 Racing magazine, the Australian, who has contested 207 Grand Prix since entering the sport (with Minardi) in 2002, winning 9 of them and finishing third in the title race in 2010 and 2011, says that although he is leaving the sport a year too soon he believes it is the right time to go.

"I've been on the edge with F1, motivation-wise, for the past couple of years," he said. "You have to be driven. You turn yourself around each winter and the fire in the belly is not quite what it was when you were twenty-four.

"I remember hearing something about sportsmen and women years ago. They were saying that as long as they could keep their motivation, they would keep going.

"I could never work out what that meant. How could you lose your motivation? But questions keep coming to me more and more often that were never there in the past. It's not about driving or racing, it's about keeping my own F1 programme going for 11 months of the year. And it's just got to the point where it's like, well, I've achieved a lot of things.

"I still enjoy being belted in the car and driving down the pit lane, which is a bit disappointing," he admitted, "but I've spoken to some really good sportsmen and women who have been at the crossroads where making the call was not easy and they messed it up.

"I'm probably leaving F1 a year too soon but with the changes next season and the opportunity to join Porsche, it's the best move for me.

Asked which aspects of the sport he won't miss, he admitted: "Travel and hotels. And probably the repetitive nature of the job. A bit of media. Lots and lots of small things that you're happy to deal with when you're bright-eyed and bushy-tailed.

"But it does, in the end, force you to ask yourself the question: 'Do I have to be here, doing this?' And when Porsche came along, I could look myself in the eye and say: 'Well, you know what, I probably don't have to do some of those things any more."