Let battle commence. Tomorrow begins the hardest Tour in recent years. The most open Tour in recent years. The most important Tour in recent years. And, if the pre-race vows of the organisers are to be believed, the cleanest Tour in recent years.

After the debacle of 1998, this edition is crucial to the event. Last year an uneasy calm descended the Tour, after the media frenzy of 12 months previously. There were uncorroborated allegations levelled against race winner Lance Armstrong, who returned from his fight with cancer transformed as a bike rider, but by and large the scandal of 1998 was absent. A drug-free Tour this year would do much to restore confidence in the event.

Veteran Tour journalist Samuel Abt has described it as "a very tough course" and it looks good for a lot of the climbers. But it is also seen as a balanced Tour; three time-trials, including a longer-than-usual prologue of 16.5 kilometres and a 70-kilometre team effort on Tuesday's fourth stage will most likely see the flyweights some minutes down when the race hits the climbs on stage 10.

From then, the shark-tooth profile will swing the balance in their favour, with two medium and five high mountain stages, including high altitude finishes at Lourdes-Hautacam, Mont Ventoux and Corchevel. One final 59 kilometre battle against the clock remains before the 3,661 kilometre, three-week Tour finishes with a stage set totally on the boulevards of Paris.

Of the contenders, most regard Armstrong as likely to become the first rider since Indurain to defend the title successfully. The 28-year-old American has prepared meticulously. So much so, in fact, that after looking ominously strong in the recent Dauphine-Libre race, he withdrew from the startlist for the warm-up Route du Sud. "My preparation is complete," he announced.

So as Marco Pantani struggles with allegations of EPO use, and Jan Ullrich with his weight and health problems - his third place in the Tour of Switzerland was his first decent showing of the year - the biggest obstacle for Armstrong would seem to be the tag of favourite.

Ullrich, Pantani, Richard Virenque, Alex Zulle, Abraham Olano and Fernando Escartin will do their utmost to deny him, but it is hard to picture someone other than Armstrong in yellow in Paris on Sunday July 23rd.