Sir Frank Williams is the longest-serving entrant in Formula One history - and tomorrow's Monaco Grand Prix will be his 600th Formula One race.

o The leader of the Grove-based Williams F1 team 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."

His first World Championship race was the 1969 Spanish Grand Prix at Montjuic Park, at which he entered a Brabham BT26 for his friend Piers Courage.

An engine problem cut short their race, but the pair went on to finish second at Monaco only two weeks later.

During the course of his four decades in the sport, he has won 113 races, seven drivers' world championships and nine constructors' world championships.

He has also been the recipient of numerous awards, including two Queen's Awards for Export, France's Legion D'Honneur, rarely awarded to foreigners, as well as a knighthood to add to his CBE in 1999.

The team's director of engineering, Patrick Head, is an integral part of Sir Frank's success, their partnership being one of the most enduring in the pitlane.

Head said: "For Frank to reach 600 Grands Prix is a hell of an achievement.

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

"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!