"I retire. I will not race (in Formula One) next year," the 37-year-old said at a news conference when asked about 2002.

"For the moment it is not completely clear what I'm going to do. For sure I will not drive F1 any more."

He was speaking only a few hours after team boss Eddie Jordan had said that Japan's Takuma Sato would take Alesi's place and make his Formula One debut next season alongside Italian Giancarlo Fisichella.

Alesi's words took Jordan by surprise and, sitting alongside, the Irish entrepreneur was clearly moved.

He immediately paid tribute to his friend while also hoping that he might be persuaded to stay on as a test driver.

The Frenchman has been linked recently to the Arrows team and has also spoken of making the switch to the American CART series. But he said last month that he was not interested in being a Formula One test driver.

Jordan hoped otherwise: "Jean said he doesn't want to race any more but I hope he's going to do some test driving," he said. "We need his experience.

"I think what he said was that he's retiring from racing."

Alesi joined Jordan in August at the Hungarian Grand Prix as a replacement for the sacked German driver Heinz-Harald Frentzen, who took his place at Prost.

The move reunited Alesi with his old mentor after an 11-year gap since he won the Formula 3000 title for Jordan.

Alesi is a remnant of Formula One's "old school," a blisteringly quick driver with sublime car control in wet conditions and a passionate Sicilian temperament that won him many admirers in his years at Ferrari.

He has repaid Jordan by scoring points in two of his four races for the team so far and, with Jordan holding an option on his services for 2002, had hoped to stay on.

But Jordan said it was time for his team, currently sixth in the championship, to undergo a restructuring and having a young and impressive Japanese talent in a Honda-powered car was clearly the way to go.

"Ferrari is too strong at the moment and (Italian) Jarno (Trulli) is going to another team. So it's time for us to restructure," he said.

Jordan said he was happy he had at least fulfilled his ambition of putting Alesi in one of his Formula One cars and emphasized the strength of their friendship.

"It's easy to love Jean. ... I have never seen any badness in him. He lived with us, in our home and with our children," he said.

"This is a very sad moment but I think it is a good one and I am proud he has driven for us, and I am proud that he got points for us, too," Jordan added.

The team boss said the decision to opt for 24-year-old Sato, the 2001 British Formula Renault champion who has signed a two-year deal, over Alesi had been one of the toughest he had ever made in Formula One.

"My heart was saying one thing, but the long-term view of the team was saying another," he said.

Jordan said Alesi understood the reasoning.

"It was not as if he wasn't being accepted for his talent. He knew why we were making a strategic decision instead of a short-term one.

"I am very, very excited about Sato," added the Irishman. "In a way it again goes to prove that Jean has often been in the wrong place at the wrong time.

"I asked him very earnestly to join us two or three years ago ... I'm just pleased he did come back to drive for us."