Jackie Stewart last night landed a £100 million birthday present after selling his grand prix team to Ford. The three-time former world champion, who is 60 today, ended months of speculation by announcing the buy-out by the American car giant.

Stewart will stay on as chairman and chief executive of the Milton Keynes based team he set-up with his son Paul, who will remain as deputy chairman.

"Ford's increased commitment to Formula One is great news for the team," said Stewart, who retired from racing after winning his third world title in 1973.

"To be competitive in Formula One these days, and to win the great benefits available, a team needs strong financial and technical support. Ford can offer that."

Stewart, already a multi-millionaire who won all his titles in Ford-powered cars, denied he had been in talks with his engine suppliers at the Brazilian Grand Prix last April.

The Scotsman hinted he had received offers from other bidders, though a buy-out by Ford - who along with Ferrari become the only manufacturer's to run their own F1 team - always appeared likely.

Jac Nasser, Ford's chief executive officer and president, said: "Ford Motor Company has a long and very successful record in auto racing. Our latest move will allow us to take our performance to the next level."

Neil Ressler, Ford's chief technical officer who is also a director of Stewart Grand Prix, added: "Our goal at Ford is to race to win.

"By buying our own team, and applying the company's comprehensive technical resources to it, I believe the Stewart-Ford team will become increasingly more successful."

Stewart won 27 times in his 99-race career before bringing his retirement forward by missing the final race of the 1973 season in America when Tyrrell team-mate Francois Cevert was killed during practice.

But he maintained his close association with Ford during his retirement and secured an exclusive five-year engine deal with the company when he set up Stewart Grand Prix in 1996 with his son.

The team made its debut at the Australian Grand Prix in 1997 and scored its first podium that year when Rubens Barrichello finished second in Monaco, though the second year was less than successful.

But their fortunes have improved this campaign and they are currently sixth in the manufacturers' championship with six points.

Barrichello led a race for the team for the first time in Brazil and also finished third in the San Marino Grand Prix.

Ford have scored 174 grand prix wins and 13 drivers' championships, although the last was Michael Schumacher's triumph with Benetton in 1994.