Lewis Hamilton puts his faith in the brains of Brawn

We don't need to ask, 'Will he or won't he?' any more.

He did.

And in among the hubbub on Friday, the gasps of disbelief, the muffled groans of McLaren fans, the sound of knives sharpening at Woking where the team's management allowed arguably the quickest driver in a generation to slip through their fingers, one question almost went unanswered regarding Lewis Hamilton's impending move to Mercedes: will it be a success? Or will it end in tears?

How could Hamilton have chosen Mercedes, who have managed one solitary win in over 50 grands prix since returning to the sport as a full works team at the start of 2010, over McLaren, who have won 16 times over the same

period and compete for championships almost every year? Surely it is career suicide; a triumph of greed over common sense?

Not necessarily. Quite apart from the fact that Mercedes team principal Ross Brawn is adamant that Hamilton will be paid less at Brackley than he would have been at Woking, the above arguments do not stack up. It is what Mercedes do in the future that matters, not the past.

Brawn is slowly but surely building something at Brackley and Hamilton has gambled on it being a success. It is a big gamble, especially when you are leaving a team as competitive as McLaren, but it is a calculated one.

Brawn's track record of winning after a lengthy building process is well established. He joined Benetton in 1991; they won drivers' crowns in 1994 and 1995 and the constructors' title in 1995. He jumped ship to Ferrari in 1996. Three years later, in 1999, the Scuderia began a run of six consecutive constructors' crowns and, from 2000 onwards, a run of five consecutive drivers' titles.

In 2007 Brawn joined Honda and using their vast resources combined with his talent for sailing close to the wind design-wise, built a car for 2009 that blew the opposition out of the water even after the Japanese manufacturer pulled out of the sport.

Then came Mercedes. By his own admission, it has not been a huge success, but Brawn has not sat on his hands either; he has been amassing an engineering army at Brackley. So many big names have arrived that some believe it may be a case of too many tech geeks spoiling the broth.

Brawn believes the proof of the pudding will be in the eating and that Hamilton could be scoffing his face as soon as 2013, rather than 2014 when most pundits agree Mercedes will have more of a chance thanks to the planned switch to 1.6 litre V6 turbos and the rise of the new ERS [Energy Recovery Systems].

"The changes we have made in the last two years will be measured in 2013," Brawn told The Sunday Telegraph.

"Geoff Willis, Aldo Costa, Mike Elliott, our new head of aero. I'm very excited about Mike. He's a really strong guy. That has to show through in 2013 and I am pretty optimistic and confident that it will."

Fans could be forgiven for being sceptical. The team at Brackley - whether as BAR, Honda, Brawn or Mercedes - have not shown much

apart from one half-season in 2009 to suggest they can consistently compete with the Ferraris and McLarens of this world. Neither have they shown, yet, an ability to develop at the same pace as their rivals during the season. But Brawn has earned the right to be judged on the end result.

Hamilton's advisers, Simon Fuller's XIX Entertainment, know little about the mysteries of Formula One engineering. But Hamilton will not have been ignorant of all these facts. Do not listen to those who would have you believe he was persuaded to move purely because of Fuller's lust for filthy lucre.

It may have played a part - there is no doubt XIX will make more money out of him at Brackley and they may have tacitly encouraged him to make the leap - but Hamilton is a racer at heart and one with a keen sense of where he fits into the pantheon of greats. He desperately wants more championships to cement his legacy.

With their signing of Hamilton, Mercedes have swept away any lingering doubts about their commitment to the sport. They have gone all in.

Ultimately, Hamilton said on Friday that it was his desire for a "fresh challenge" that fuelled his move, and there is no reason to doubt his word. His relationship with McLaren was never so bad as to be irrevocably broken, but there was a sense at times over the last two seasons that both sides could do with a fresh start.

Perhaps that led to complacency on McLaren's side in their negotiating tactics. Perhaps they were not so desperate to keep him.

Whatever, it is done now. At Mercedes Hamilton has the chance to grow in a new environment, to help build a winning team rather than be part of a ready-made one.

It is a bold and exciting decision on his part; a fantastic coup for Mercedes; a blow for McLaren (pending Sergio Perez's emergence as a championship contender); and great news for Formula One in general.