Preview of Le Mans, racing's toughest test

The place also reeks of history. Most of the track still follows the public roads used throughout the history of the race, including corners with names such as Arnage, Tertre Rouge and Indianapolis, not to mention, of course, the massive Mulsanne Straight, once more than 3½ miles long but now divided into three, roughly equal 1.2-mile sections.

Le Mans also put British motor racing on the map: before then, Britain had an almost non-existent record in racing, but then Bentley won five of the first eight Le Mans and placed Britain at the forefront of the racing world.

The story of Le Mans has also been tinged with tragedy. The number of drivers who have lost their lives here - 24 - actually compares favourably with the numbers who have died at the Nürburgring or Indianapolis, but when you count in marshals and spectators (including more than 80 who died at Le Mans in 1955 in the worst accident in the history of motor racing), more have died at Le Mans than any other circuit.

Le Mans has also attracted a number of celebrity racers over the years. The most successful was the actor Paul Newman, who nearly won it in 1979 driving a Porsche 935 but had to settle for second. Nick Mason, Pink Floyd's drummer, raced there five times between 1979 and 1984 while Steve McQueen - probably the most naturally talented of all celebrity racers - was prevented from competing by insurance issues. Instead, his obsession with the race led him to finance and star in a film called Le Mans, which was mauled by critics and flopped at the box office but has still become a cult classic.

This year Patrick Dempsey, the star of Grey's Anatomy, the medical drama, will make his first Le Mans start driving a Ferrari F430 in the GT2 category, and Lord Drayson, Britain's science minister, will become the first serving member of the government to compete in the race. He teams up with Mason's soon-to-be son-in-law Marino Franchitti in an Aston Martin Vantage in the GT2 category. Luc Alphand, a French former champion downhill skier, will compete for the ninth time, driving a Chevrolet Corvette.

Who's going to win?

Le Mans is divided into categories but the overall winner is the car that goes furthest in the 24 hours, which invariably means one of the purpose-built prototypes. It will be a huge upset if victory goes to anything other than an Audi or a Peugeot. Last year Peugeot's 908 was the class of the field but mechanical frailty gifted victory to Audi's slower but steadier R10.

This year Peugeot should have sorted out its reliability issues, but the car is up against Audi's all-new R15, which has proven to be outstandingly fast and consistent. With eight wins in the past nine Le Mans, you'd be brave to bet against Audi. And if it achieves that ninth win, it will equal the number of victories achieved by Ferrari over the years, leaving it second only to Porsche with its almost unassailable 16 wins.

What chance does Aston Martin have?

A slim one. For the past two years its DBR9 race cars have won the GT1 class at Le Mans but this year Aston Martin has three cars in one of the Le Mans Prototype (LMP) categories, so it can fight for outright victory. If the team wins, it will be on the 50th anniversary of Aston's only victory in the event to date.

The problem is that the way the Le Mans rules are drafted confers a huge ad­vantage on diesel cars. Aston's machines (which were designed by Lola but are powered by Aston Martin, and should be called Lola-Aston Martins) use a highly tuned derivative of the 6-litre V12 petrol engine found in its road cars. There are nine diesel cars in the class, including three each for Peugeot and Audi.

Aston's problems have been compounded by the fact that this year's test weekend was cancelled to save costs, so the first time any of its cars ran on the circuit was last Wednesday. In the event, "best of the rest" is the most likely outcome for the British team.

What about the other categories?

At Le Mans 55 cars race in four different categories: two for pure racing cars, or prototypes (LMP1 and LMP2); and two for cars loosely based on something you can buy from a showroom (GT1 and GT2). The technical regulations for each class require a degree in automotive engineering to understand, but basically, while an LMP1 car will have around 650bhp and cannot weigh less than 900kg, LMP2 cars are about 100bhp less powerful and 75kg lighter. GT1 and GT2 cars all must weigh at least 1,125kg but the GT1 have around 600bhp compared with 450bhp-500bhp for the GT2s.

On the track the prototypes should have no problem outpacing the GTs thanks to their purpose-built design and substantially lower weights.

Who's going to win which class?

Well, we'd plump for Audi in the LMP1 category but things are likely to be much more hotly contested in the LMP2 class. However, we'd go for the Porsche RS Spyder, which is a proven package designed by the most successful manufacturer in the history of the race. Porsche walked this class last year but can expect stiffer competition this weekend from the likes of Lola and Zytek.

The GT1 category, having provided most of the really exciting racing at Le Mans in the recent past, looks strangely bereft this year, not least because of Aston's decision to upgrade to the LMP1 class. Just six cars are entered and with four of them being Corvettes, it's not hard to hazard a guess which marque is going to come out on top. The other two are a privately entered Aston DBR9 and a Lamborghini Murciélago, which, if reliable, might just give the Americans something to think about.

In many ways the most exciting category is the "entry level" GT2 class. With 17 entries, the GT2s make up almost a third of the field and should see a titanic struggle develop between the five Porsche 911 RSRs and 10 Ferrari F430s. Ferrari dominated last year, and sheer weight of numbers suggests the odds are in its favour again, but as many have found out over the years, you underestimate Porsche at your peril on this track.

Last year Ferrari cruised to victory, largely because the two leading Porsches took each other out early in the race, but the Italians cannot expect the Germans to be so accommodating this time. And with Luca di Montezemolo, Ferrari's president, there to act as official race starter, all the pressure to perform will be on those driving the Italian cars.

The GT2 is the category in which Drayson has entered his Aston Martin V8 Vantage. Keeping up with the quickest Porsches and Ferraris is perhaps an unlikely outcome but - as for most teams competing at Le Mans - if the car is still running at the end, that in itself will feel like a victory.

Wish I'd gone now. Will it be worth going next year?

Almost certainly. The British love affair with Le Mans is almost as old as the race itself - more than 35,000 fans make the trip across the Channel every year - meaning more Brits go to Le Mans than any other motoring event, except the British Grand Prix and the Goodwood Revival.

Nor do you need to be a motor racing geek to enjoy it. Many spectators go for the drive there and back, the camaraderie in the campsites and the unique atmosphere at the track. Hardly anyone watches all the racing, and most spend more time drinking beer or enjoying the delights of the famous funfair than standing at the side of the track, observing the cars fly past. That said, to be at one of the far-flung corners of the circuit at dawn, watching brake discs glow red hot as the cars decelerate from more than 200mph, is one of the greatest sights that any true race fan can experience.

Better still, next year the race rules are tipped to be changed to try to ensure the days of the diesel steamroller are no more. With other manufacturers waiting to take part as soon as they feel they have a chance of winning, the view among the Le Mans cognoscenti is that this historic race is on the verge of a new golden era. Don't be the one who misses it.