Mark Webber leads Le Mans for Porsche after six hours

The number 17 Porsche, which the ex-Formula One driver shares with New Zealander Brendon Hartley and Germany's Timo Bernhard, led the number seven Audi of defending champions Benoit Treluyer, Andre Lotterer and Marcel Fassler.

Audi, who are chasing their 14th win in 16 years, had their number nine car in third place ahead of the remaining two factory Porsches.

Porsche had swept the top three places in qualifying thanks to their lightning one lap pace but Audi showed they were formidable foes in race trim and traded the lead during the afternoon.

The safety cars, three of them to cope with the long Le Mans lap, made their first appearance at the end of the first hour when a three car collision dumped oil on the track at the first chicane.

There was a much longer safety car interlude at the end of the third hour, when Frenchman Loic Duval spun and hit the barriers in the number eight Audi at the Indianapolis corner, with Porsche then filling the top three slots.

Duval managed to nurse the car back to the pits and it resumed the race only four minutes later, with the safety car leading for 45 minutes.

Nine times winner Tom Kristensen, the great Dane who retired last year, had waved the 83rd edition of the race away in bright sunshine, watched by an estimated crowd of around 250,000 spectators enjoying the festival atmosphere.

Audi have been the dominant team at Le Mans in recent years with their diesel hybrid car but face a tough battle from Volkswagen Group stablemates Porsche.

Porsche have triumphed 16 times, with their last victory coming in 1998.