Reigning MotoGP World Champion Casey Stoner has announced he is to retire from MotoGP, and racing, at the end of 2012.

The two-time champ, who said to bikesportnews.com at Jerez that it wouldn't be long before he packed it all in, delivered the news at the beginning of today's Le Mans MotoGP press conference.

“This has come after a long time of thinking and talking with my family and my wife. It’s been coming for a couple of years now. At the end of this season I will finish my career in MotoGP and follow different things in my life. After so many years of doing the sport I love, for which myself and my family have made so many sacrifices, this sport has changed a lot and it’s changed to the point where I’m not enjoying it. I don’t have the passion for it, so it’s better if I retire now. It’d be nice if I could say I’ll stay one more year but then when does it stop, so we decided to finish," said Stoner.

“My decision isn’t going to change anything this season. We still want to win races and we’ll still put in 110 per cent of effort and maybe even more I’ve been watching this championship for a long time and it’s easy to see what works and what doesn’t.

“There are many, many different reasons but basically it’s me losing my passion for the racing and my enjoyment for the sport. Sure, I’m going to enjoy this year but I’m sure if I continue it would be a mistake.

“There’s many things I’d like to do with my life. I don’t want to keep racing bikes to the point where I lose my passion for motorcycles. I love bikes, they’ve been my whole life, and if I keep doing this I’m afraid I’ll completely lose my passion. Maybe I’ll still have some involvement in the sport, if I can find the energy, to maybe help some young riders, things like that.

“We’ve had a great career, we’ve had some fantastic races and I feel even after my first championship in 2007 I’d already reached my goal. This was my dream: to be World Champion. It’s been a difficult up and down road but a fantastic one. I won’t have any regrets.”