The Launceston race contender was descending at about 70km/h when he lost control on the narrow, twisting Mont du Chat, near Chambery.

After veering off the road on the inside of a left-hander, Porte hit the tarmac hard, slid into rival Dan Martin before the pair smashed into a wall of rock.

Just 11 months after a similar crash in Rio de Janeiro saw Porte exit the Olympic Games with a broken shoulderblade, he sustained fractures to his collarbone and hip as well as extensive abrasions.

With several other accidents also occurring on a rain-soaked treacherous day in the Jura Mountains, Tour organisers soon came under fire for creating a stage that many riders – including Porte – had previously highlighted as being unnecessarily dangerous.

Sitting fifth in the general classification, Porte was well placed on the 181.5-kilometre ninth stage from Nantua when the accident happened 20km from the finish on the last of seven climbs for the day.

The BMC Team leader remained conscious throughout the ordeal, talking to medical staff as they treated him on the tarmac.

After being put in a neckbrace, Porte was stretchered to an ambulance and transferred to the Centre Hopitalier Metropole Savoie in Chambery where he underwent X-rays to determine the extent of his injuries.

BMC Racing Team chief medical officer Max Testa said: “His condition was stable from the beginning, he was responsive and he remembered everything that happened before and after the crash.

"X-rays confirmed a non-displaced right clavicle fracture and a non-displaced right acetabulum (hip) fracture. Richie also suffered extensive superficial abrasions involving the right side of his body.

“At this stage, the injuries will not require surgery. The plan is to re-evaluate Richie [on Monday] morning and confirm that he is stable enough to be transferred home."

Having assisted with the aftermath of the crash, sports director Fabio Baldato was visibly shocked as he updated reporters at the BMC bus after the stage.

"We are all sad. We did a lot of work," Baldato said. "First Richie did a lot of work for this Tour de France from the beginning of the year. We did a lot of training, recon, training camps ... we did everything possible to put him on the podium from the first day all the team was around him. 

"We just can be next to Richie and wish as soon as possible come back stronger because … he deserved a good result, a great Tour de France. This year [he was] super good."

Teammates and rivals united in sympathy for the Tasmanian, including friend and race leader Chris Froome who had also seen his Sky teammate Geraint Thomas crash out with another broken collarbone.

"Obviously for us losing Geraint was massive and for the race to lose Porte also is a big blow to the race," said the Brit.

"No one wants to see a big contender like him go out like he did today. That was horrific."

Porte's Belgian teammate and Olympic champion Greg Van Avermaet added: "It is very hard for us because we came here with one goal and that's to put Richie on the podium in Paris. He was really good. He was in good shape.”

Dr Testa confirmed that Porte will require a minimum of four weeks off the bike.

"Normally, a fractured clavicle and pelvis would require four to six weeks' recovery, providing there are no complications,” he said. 

“If everything goes to plan, Richie could be back on the bike at the beginning of August and slowly build his fitness up from there. Based on Richie's recovery, we will re-evaluate his program for the rest of the season in consultation with BMC Racing Team management."