Mark Webber insists that leaving F1 at the end of the current season is the 'best move' for his career, despite admitting that he could be walking away from the sport a year too soon.

Webber revealed earlier this season that he would join Porsche for its new LMP1 sportscar programme next year, with Red Bull having signed fellow Australian Daniel Ricciardo as his replacement.

The 37-year-old will leave F1 after a twelve-year career that also saw him race for Minardi, Jaguar and Williams, and even though he felt he could have gone on for another year, Webber said the time was right to talk away.

"I've been on the edge with F1, motivation-wise, for the past couple of years," he told F1 Racing magazine. "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 24.

"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 eleven 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, 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."

Despite saying he would miss some of the competition on track, Webber added that there were also plenty of things he wouldn't be so sad to see the back of.

"Travel and hotels," he said, "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."