MONTE CARLO, May 22, 2008 (AFP) - Long-serving British team chief Sir Frank Williams this weekend celebrates his 600th Grand Prix.

But typically the man who founded his own team and then went on to see them win 16 world titles said he did not care at all about the landmark.

Now Formula One´s longest-serving team boss, Williams has played down the significance of the anniversary and his remarkable achievement.

He is severely disabled and has been a quadriplegic since a serious road accident in France in 1986.

He said: "As most people would expect, reaching 600 Grands Prix means very little to me. I do have to admit, however, that there have been some brilliant moments over the 40 years that I´ve been racing, and there have also been some moments of great sadness.

"Most of the time it has been a most pleasurable experience. If I was 40 years younger, I would still choose the same path towards where I find myself today."

Patrick Head, Williams´ engineering director and Sir Frank´s long-time right-hand man, reckoned Williams´ milestone was "a hell of an achievement.

"I know this will sound rather trite, but he really loves Formula 1, and motor racing in general, and I think that´s the secret of his longevity," Head said.

"Frank employed me in November 1975, since when I haven´t seen much change in him, except for the obvious physical changes as a result of his accident in 1986.

"When we first started working together, I suppose you could say he was a bit like Tigger (of Winnie the Pooh fame), full of enthusiasm and excitement. "Since his accident, he´s become a deeper thinker and much more strategic, and I think that has benefited the team.

"Being Frank, I expect him to be the least interested person in the 600 celebrations in Monaco. He´ll be too busy thinking about the future." Williams´ world champions have paid tribute to him.

"His situation is unique because he really is the last team principal in the pit lane that goes motor racing for its true essence, and that´s to race," said Keke Rosberg - who won the 1982 title for Williams and is the father of the team´s current lead driver Nico Rosberg.

"He has a great team around him, and I hope Williams get back to winning because that is the only thing that matters to Frank."

Williams made his debut as an F1 entrant in 1969, and has since seen his cars win 113 GPs, seven drivers´ titles, and nine constructors´ championships, most recently in 1997.

His blackest day came at the 1994 San Marino Grand Prix when three-times world champion Brazilian Ayrton Senna died in a Williams car.