Villeneuve and Montoya clash in drivers' briefing

Villeneuve had earlier accused the Colombian of 'being on a mission' as, he said, Montoya blocked him for the fifth or sixth time this season during Friday's practice.

And Montoya was fuming that Villeneuve driver brake-tested him a few corners later - resulting in the BMW-Williams running into the back of the BAR.

Villeneuve confronted Montoya as they walked to the drivers' briefing. Then, when it continued in front of the other 20 drivers, tempers boiled over. A scuffle ensued as Villeneuve grabbed Montoya and the duo had to be separated by Race Director Charlie Whiting.

As insults were thrown Montoya allegedly hurled accusations at Villeneuve over the Australian Grand Prix crash when the Canadian went into the back of Montoya's team mate Ralf Schumacher and marshal Graham Beveridge was killed by a flying wheel.

Villeneuve was the one to suffer on the track in Canada because he continued to circle after the collision and it is thought his damaged suspension broke, hurling him into a crash barrier going up the hill towards Pont de la Concorde. The impact was so severe it destroyed the monocoque and Villeneuve used a new one for qualifying.

A source in the paddock said: "It was a pretty vicious confrontation between the two of them in the briefing."

The previous day Villeneuve had lashed out at Montoya: "I am upset because it must be the fifth or sixth time this year that he's blocked me - he's on a mission or something."

"Normally when you get blocked - I've blocked some people also - you try to get out of the way and sometimes you don't make it, but you still make an effort and give room to the other person.

"It seems that Juan, every time he sees someone in the mirror, he slows down and stays on the line purposely so I really don't know what kind of game he's trying to play."

But Montoya, who like Villeneuve took the American Champ Car title and an Indy 500 win before moving to Formula 1 with Williams, was unrepentant.

"I don't know anything about a mission," he said. "He got pissed off at me and thought I should move earlier. I got to the next chicane behind him and on the exit he stood on the brakes.

"It's a place where you are accelerating really hard. I hit him but I don't think I hit him really hard. I braked as hard as I could to try and stop. I don't know what he was thinking when he braked but he paid for it."

The pair's confrontations started at the first race in Melbourne in March. "In Australia I blocked him a bit and he hit me," admitted Montoya. "I went to see him and said I was sorry because I blocked him."