As the Formula One cars made their first appearance under dark clouds at the Circuit Gilles Villeneuve, there were fears protesters could spoil a weekend party that pours millions of dollars into the local economy.

Having already cancelled Thursday's free access day for spectators due to fears that student demonstrators may try to hijack the event, officials beefed up security for Friday's practice sessions.

There was an unusually heavy police presence at entry points to the Isle Notre Dame venue, an artificial island in the St Lawrence seaway.

For weeks, protesters have been promising to disrupt the Grand Prix and on Thursday they targeted a gala evening where they were confronted by hundreds of riot police in a tense standoff that resulted in several arrests.

Protesters elsewhere stripped down to their underwear, or went naked, and marched towards Crescent Street - party central for the Formula One weekend - taunting well-heeled revellers as they pushed their way into the avenue's posh bars and restaurants.

The sometimes violent student strike, which began in mid-February after the Quebec provincial government announced plans to raise tuition fees, has taken on a wider scope with groups opposed to global capitalism, anarchists and labour unions joining in.

OBVIOUS TARGET

With Formula One viewed as an elitist sport, the Montreal race provided protesters with an obvious target and raised tensions among police and race organisers.

Skirmishes are expected to continue throughout the weekend with protesters reportedly planning to overload the Montreal subway system that provides the main link to the circuit.

A far more serious concern, from a safety perspective with cars hitting speeds in excess of 300kph, would be any attempt to invade the track during Sunday's race.

The Convergence of Anti-Capitalist Struggles (CLAC-Montreal) warned on its website (www.clac-montreal.net) that it will "participate in a week of economic disruption around the Grand Prix Formula One in Montreal".

"We will not shut up; the power of the streets is stronger than your sham democracy," said the CLAC. "The Montreal Grand Prix is the perfect opportunity to make this message heard."

The student unrest has already had an economic impact on the race which, according to organisers, for the first time in many years will fail to sell out.

There are other signs that protests are having an affect with hotel rooms that usually go at a premium now being offered at a discount.

For F1 drivers and their teams, however, the protests have had little impact.

Cloistered safely away out of view of the public, life goes on as usual inside the well protected paddock area where wealthy guests can sip on expensive champagne and dine on lavishly prepared meals.

"Obviously I'm not completely up to speed with what's going on...some of the students are not happy with certain things," said Red Bull's Mark Webber, who will be looking to follow up his victory in Monaco with a win in Montreal.

"I'm not saying it's a minority, but sometimes when there's a little bit of tension then some other people can lose out."

(Reporting by Steve Keating in Montreal, editing by Alan Baldwin)

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