Chris Froome hits back at doping allegations

Froome (Team Sky) leads by three minutes 10 seconds from Nairo Quintana (Movistar) with five stages remaining, four of them in the Alps where the yellow jersey will be won. The race finishes in Paris on Sunday.

The 2013 champion was part of the 'big four' entering the race, but defending champion Vincenzo Nibali (Astana) and Alberto Contador (Tinkoff-Saxo) have endured challenging races and Quintana, runner-up to Froome two years ago, is expected to find his best form in the Alps.

Froome has been subjected to innuendo and interrogations over his dominant win to La Pierre-Saint-Martin on stage 10, when Team Sky colleague Richie Porte was second, 59secs behind, and Quintana third, 1min 04secs adrift, as May's Giro d'Italia winner Contador and, in particular, Nibali struggled.

Rather than assess his rivals' under-par performances, Froome's detractors have focused on his display with some concluding he must be doping. He insists he races clean.

"It just seems strange to me," he said.

"I've got to admit it is frustrating to an extent that if you look at the last five Grand Tours that have been won by different teams, different riders, there hasn't been the same kind of outcry for power data and numbers and all the rest of it.

"Unless I'm missing something, I didn't see the same kind of level of questioning.

"I don't really understand why now it seems to be such a hot topic in this year's Tour de France, given that, okay, I won one mountain-top finish by 59 seconds."

Host broadcaster France 2 on Sunday broadcast an expert analysing Froome's ascent in the first Pyrenees stage, with Pierre Sallet concluding his power profile of 7.04 watts per kilogram was "abnormally high".

Sir Dave Brailsford is reportedly considering releasing performance data to support his defence of Froome, with the possibility the Team Sky principal may choose to address the ongoing insinuations on Tuesday's rest day.

Brailsford has always stated it is not possible to prove a negative - that Froome is drug free - and such a data release could invite more questions than answers for a media and public sceptical after years of drug-riddled performances at the Tour.

"The power data is obviously the intellectual property of the team and if they're happy to give that out then of course I support that, no problems," Froome said.

Froome can rely on the support of Geraint Thomas in his bid to win the Tour for a second time after the Welshman laughed off a dramatic crash which saw him clatter into a telegraph pole on Monday's 16th stage, won by Spaniard Ruben Plaza (Lampre-Merida).

Plaza held off Peter Sagan on a daring final descent of the Col de Manse, where Thomas was nudged off a precipice by Frenchman Warren Barguil (Giant-Alpecin).

The 29-year-old from Cardiff flipped over his handlebars and tumbled off the road, smacking the telegraph pole.

Amazingly he recovered to finish 38 seconds behind the group of main contenders, including Froome, and preserve his sixth place overall.

"The doctor asked me a few questions, my name and stuff. I said 'I'm Chris Froome'," Thomas said.

Referring to the abuse Team Sky has encountered earlier in the Tour, Thomas added: "A nice Frenchman - they are nice here sometimes, they're not all bad - pulled me out."