Former F1 driver Derek Warwick believes Lewis Hamilton has probably made a big mistake switching to Mercedes next season.

Hamilton opted to sign a three-year deal with the Brackley-based outfit back in September, thereby ending his 14-year relationship with McLaren. However, given the form of Mercedes in 2012, Warwick is fearful the 2008 F1 world champion will now be reduced to the role of a bit player.

"You are never going to see McLaren, Red Bull and Ferrari out of the top three and I'd say McLaren and Red Bull are favourites to fight it out again [in 2013]. It just depends on which way round they finish at the top," Warwick told British newspaper, The Daily Star earlier this week.

"And the great thing Red Bull have is a certain gentleman called Adrian Newey, who is without doubt the best designer and race car engineer there is in F1. Every team he has gone to, from Williams to McLaren and now to Red Bull, has won World Championships.

"We have a stability in the rules for next year so you would suspect we will pick up at the start of 2013 where we left off this year.

"I am sure Lewis Hamilton will hope that is not the case. Mercedes are working on a new car but their performance this year was not just disappointing, it was very, very poor.

"Mercedes have undoubtedly the fastest driver in F1 and we all want Lewis to be in a winning car next year and challenging.

"I desperately hope Mercedes will be competitive but either Lewis knows something we don't or he's lying in bed at night thinking, 'What have I done!'" Warwick added.