Martin Whitmarsh says Lewis Hamilton might be regretting his move to Mercedes

McLaren boss Martin Whitmarsh believes Lewis Hamilton is already having regrets over his move to Mercedes next season.

Hamilton's deal with Mercedes, which lasts for three years and is said to be worth £45million, was announced the week after the Singapore Grand Prix. That retirement dealt a crucial blow to Hamilton's title hopes and was one of a number of reliability problems McLaren have recently suffered. Hamilton was similarly leading in Abu Dhabi last weekend before retiring with a fuel pressure problem, while the team also bungled a number of pit stops earlier in the season. In Spain, meanwhile, Hamilton had qualified on pole position but was then sent to the back of the grid after the team accidentally underfuelled his car. McLaren are still seen as much the better prospect next season, although Mercedes will hope to make gains in 2014 on the back of new engine rules. Asked whether Hamilton has regretted his decision, Whitmarsh replied: "I think he has on occasions, yes. Probably, when you make a decision you have to tell yourself that the decision is made so you have to look forward. "You say okay, that it is in the past so you don't spend too much time thinking about why. You just look forward and make the best out of the new situation."