Froome maintains lead in mountains

Last week, it was reported that Alberto Contador, the Tour of Italy victor, had faced no doping questions during his ride to victory this May.

On Wednesday, Quintana attacked early into the 161km stage but never managed to drop Froome, while Contador also tried his luck 75km from the finish, in the ascent to the col de la Colle St Michel.

Froome’s problem was later reported to be a stone in his brakes which he had to get rid of before chasing back to the group that contained his closer challengers.

The possibility of a second Briton on the podium remains, with Geraint Thomas (Team Sky) fourth, but the Welshman’s priority is to help Froome’s bid for glory.

Vincenzo Nibali promised much prior to this year’s Tour de France.

Froome was not aware of the television footage which appeared to show a roadside spectator spitting on him.

They will go over the highest point of the Tour in the Col de la Croix de Fer (also climbed on Stage 18) whilst the other climbs are category one and two.

Reflecting afterwards on a tight stage, overall leader Froome said: “It was a massive day”. So rather than hunt down the Movistar rider, Froome rode steadily, telling himself: “I don’t need to panic but I do need to keep something in reserve”.

“It’ll be our last challenge, we can expect a grand finale”. Faced with speculation that has swirled around his performances this year, Froome argued: “I was quite sure when we released the file it wouldn’t be enough”.

Nairo Quintana may be running out of options at the Tour de France but he says the next two Alpine stages will favour him over race leader Chris Froome. “I can’t wait to get up there”.

Froome’s criticism of Nibali represented a further deterioration in the pair’s relationship, after they were involved in a heated exchange over the cause of a crash on stage five. “In my opinion you don’t do that to the race leader, it’s not sportsmanlike”.

Quintana, meanwhile, runner-up to Froome two years ago, vowed to go for glory. “It’s impossible to prove a negative and it’s hard to come up with different solutions to prove that we’re clean”, he said. He has been spat at, called a cheat by people in the crowds and even had urine thrown at him during the three-week event. Froome pulled up by the side of the road to deal with the mechanical issue.

Team Sky did not follow and allowed defending champion Vincenzo Nibali (Astana) to escape too, but the British squad reacted when Valverde and Quintana accelerated.

“That was the moment Nibali decided to make his move”.

Nairo Quintana will be aiming to cement the special relationship between Colombia and Alp d’Huez when tackling the mystical Tour de France climb on Saturday.

Nibali heard about the ruckus behind him and leaned into the task.

“We (Team Sky) use the Monaco Institute of Sport for our riders who are down there”, said Froome, confirming he had undergone pulmonary function tests, to measure how well his lungs work, under Dr Bermon’s supervision.

He reeled in lone escapee Pierre Rolland on the next climb and then dropped the Frenchman on the final ascent of La Toussuire.

Upon catching Rolland and reaching the summit of the Col du Glandon, Bardet launched an attack of his own on the descent and quickly built up a 30 second advantage on his rivals.

Sweat pouring off his legs, he rode solo to the finish, with the cross from the chain around his neck in his mouth at the end. But the 2013 Tour champion held his nerve to contain any severe damage by Quintana.

That descent returned the riders to the start town of Saint-Jean-de-Maurienne with 19km to go, one kilometre before the day’s final climb began.