Seven races into the 2003 Formula One season and there is not a fan who would criticise the spectacle which the sport has delivered on the back of last season's boring, processional Michael Schumacher/Ferrari double act. But this weekend, even as the teams prepare for tomorrow's Canadian Grand Prix in Montreal, F1 is overshadowed by the world's greatest race: the Le Mans 24-Hour.

The world's greatest race? Don't doubt it. While the F1 guys spend the best part of nine months and 17 races to cover around 2900 miles, the leading cars of the 48 which will start today's 71st running of the famous endurance race at the 8.45-mile Circuit de la Sarthe will complete in excess of 3200 miles in one 24-hour run.

Each car is restricted to three drivers with none of them being allowed to drive for any more than four hours in a six-hour period or for more than 14 hours in total. And while upwards of 15 technicians swarm round a F1 car when it pits, only four are allowed to work on the car at Le Mans, and that includes refuelling.

The past three years have been dominated by the open-topped Audi R8, debuted by Scotland's Allan McNish in 2000. He was the fastest man on the circuit and denied a famous victory only when the German management ordered him to slow down to allow their countryman Frank Biela to claim the glory.

This weekend's race, though, is shaping up to be a monumental battle between Audi and Bentley.

Don't start reaching for your Union flag just yet. Remember, Bentley is owned by the giant Volkswagen Group which, interestingly, also owns Audi. But you can dispel any thoughts of team orders. Audi is not running a works team this year, instead the three cars are being run privately, two by Florida-based Champion and the Japanese Team Goh, and the third by Audi Sport UK.

While the British-entered car has a cosmopolitan driver

line-up of Biela, England's Perry McCarthy and McNish's former Toyota F1 team-mate Mika Salo from Finland, the two big Bentleys have a strong British core.

Guy Smith partners Le Mans veterans Tom Kristensen from Denmark and Italy's Rinaldo Capello, while the lead Bentley is in the hands of Australian David Brabham and Brits Mark Blundell and Johnny Herbert. Blundell is happy to sit out his fortnightly stint as an F1 pundit for ITV, while Herbert is desperate to get on with the action.

''There's no doubt the spotlight is on us this year,'' said Herbert, who captured the only F1 victory for Jackie Stewart's Grand Prix team at the Nurburgring and who led Mazda to victory at Le Mans in 1991.

''Everybody knows Bentley has a great chance of winning this year because we've proven that we're the fastest car in the field. Of course the race is completely different to the 24-hour test we did at Paul Ricard and going fastest in qualifying, but I firmly believe we have everything in place to allow us to fend off the Audis and claim a historic win for Bentley.''

Of all the manufacturers competing this weekend, Bentley is the only one which contested the first Le Mans in 1923. It is also 73 years since Bentley recorded its fifth and last win in the race. Biela, meanwhile, admits the Bentley Boys start favourites but knows unreliability is their Achilles heel.

''If the Bentleys are going to run through the whole 24 hours without any problem, then I'm quite sure there is no way for us to beat them,'' he admitted. ''They are just quicker than us, it's as simple as that. Even if they have to stop for fuel a bit earlier than us, I don't see a chance to beat them speed-wise or lap time-wise.

''But there is a chance they will run into trouble - perhaps a much bigger chance than for the Audis, which have proven themselves over the past three years to be bulletproof. We won it three times in a row with very little problems, and there's no reason why we'll have any more difficulties this year.''

So what's the key to the event which gets underway at 4pm local time today? The Bentley is faster, at least 15mph on the long Mulsanne Straight. Those extra horses demand more fuel, though, which means more stops. Expect the Audis to last a full lap longer on the same fuel load.

The Bentleys also run tyres which are two inches narrower than the Audis and though Michelin, which supplies both teams, has been developing a special compound for the manufacturer, the jury remains out as to whether Bentley will be able to triple-stint its tyres through the night as Audi does. If it can't, it's more pitstops, more lost time and a bigger advantage to the Audis.

Quite honestly, it's too close to call.