Though he has yet to even sit in one of their cars, McLaren boss Martin Whitmarsh suggests that Lewis Hamilton has had the occasional second thought, regretting the move that sees him switch to Brackley next season.

Talking to the official Formula One website, asked if he though Hamilton had possibly regretted his decision, Whitmarsh said: "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.

"Right now we still want to win races," he continued. "We are motivated by that and our conversation circles around that. And maybe he is completely dispassionate about it, but my guess is that we both will have very emotional moments in Brazil. When the separation has arrived."

While Whitmarsh has no doubts that Hamilton has had his regrets, he is, as yet, unclear as to what the factors behind the driver's decision were.

"The simple answer is that I don't know," he said. "Lewis would be able to answer that question much better than me. If I were speculating there are a number of factors and the prime one, I think, is that there comes a time when a man feels he has to flee the nest. I think it was a bit of that and a range of different emotions. He has been with us for so many years that I do not fully understand it.

"We made Lewis an offer - an offer, which I believe is more money than any other driver at the moment is being paid. That leads us to suspect that our competitor and our partner Mercedes-Benz offered a bit more money. I don't know that, but I think for Lewis made his decision. I am disappointed in one sense, but you have to focus on going forward."

Reminded that just three months earlier he had said he was sure Hamilton would remain with the team, Whitmarsh admits: "In fairness, if I had said three months ago that Lewis might leave I probably would have made some fantastic headlines, but that wouldn't have been in our interest. It would have created a lot of disturbance and pressure.

"Let's speak frankly," he continued. "The media try to create entertainment from our faux pas. Imagine if I had said Lewis was going to leave. It would have been immensely destabilizing and honestly I didn't think that he was going to leave. I was surprised, but I was not shocked. He told me right after Singapore and I am pretty sure he hadn't made up his mind until after Singapore - the Monday or Tuesday after Singapore. I think it is always bad to make a decision in the aftermath of a bad race. He was pretty sure that he was going to win that race and it was a disappointment and as I just said it is never good to make a decision in such a situation. I respect his decision, but I believe that he would be better off with us - we are the stronger team - and we intend to beat him next year!"

Hamilton, has said that joining a "big team" like Mercedes is a fantastic opportunity. Asked about such a comment Whitmarsh replied: "You have to justify your decision. He is not going to say 'hey, they offered me more money'. He is also not going to say that he's made an awful mistake. I hope he thinks today that he's made an awful mistake and I hope he thinks that next year. He's made that decision and he has to live with that decision. I have known him since he was 11 and worked with him since his teens and I know we will both be very emotional after Brazil. We have had one or two emotional moments since the decision was taken and I believe, but you must ask him, that we have a very good relationship.

As Hamilton moves on, the Woking outfit prepares for the arrival of Mexican hot-shot Sergio Perez. Bearing in mind that the Woking team gave Hamilton his big break, Whitmarsh is asked if he enjoys working with (relatively) inexperienced drivers.

"Some of the greatest moments in my life I've had when working with Mika (Hakkinen) when he was young. And we won the world championship with Mika. And with Lewis, when he was young, so I am excited.

"It is a risk taking on a young driver. Bear in mind that when we took on Lewis he was the same age as Sergio is today and he was incredibly young, incredibly raw and incredibly talented. Now when Sergio gets to Australia in 2013 he will arrive with the kind of pressure that he can't imagine right now. If you are a Ferrari or McLaren driver the scrutiny you are going to have is probably greater than a Red Bull driver and certainly more than Mercedes or any other team. At the first race, if he is not on the first two rows and fighting for a win the pressure will start to ramp. He doesn't know that yet..."

The Englishman had some words of warning for the youngster, explaining that now he's on McLaren's books his work rate will increase considerably.

"He will spend a lot less time in Mexico than he realises at the moment," he said, laughing. "That means he will be in the simulator, will be with the race engineers, he will be with the strategy people, he will be with the general engineering team, he will turn up considerably fitter and stronger than he is today.