Hakkinen's place at McLaren will be taken by Finnish compatriot Kimi Raikkonen who has shone for Sauber this season.

But while Hakkinen insists it is merely a career break, sources close to McLaren have told BBC Sport Online that the Finn is in fact retiring and does not intend to return to Formula One.

However the door will remain open to Hakkinen should he change his mind.

In a statement issued on Friday, Hakkinen said: "Formula One has virtually been my whole life since I started karting in 1974.

"Whilst this year has been difficult for me and the team, these experiences have not guided the decision to take this break."

Hakkinen, who made his debut in 1991 and won the world title in 1998 and 1999, has had a miserable season.

The Finn has failed to complete six races and lies fifth in the drivers' points race, with his only victory coming at Silverstone.

"I asked the team for a break which would be a good way to recharge my batteries and enjoy more time with my wife Erja and my son Hugo," Hakkinen added.

"Of course it might have been easier to retire, but that just isn't a decision I feel ready to take.

"I know that I will have to work hard to return after my break, but I know that I want to return with West-McLaren Mercedes."

"Mika and myself have been team-mates for six years - the longest ever in Formula One.

"We have worked well and competed hard and I understand his reasons for having a break.

"Thanks to Mika, I have gained valuable insight into fast Finns which I am sure will be useful next year."

McLaren boss Ron Dennis forged a close bond with Hakkinen after seeing him almost killed at the 1995 Australian Grand Prix in Adelaide.

He said: "Mika has always done an incredible job for us, and now is not the time to be bidding him farewell."