"One of our commissaires saw him holding on to a motorbike on the Mortirolo climb,” Jury president, Vincente Tortajada, told Cycling Weekly.

Froome held on to a police motorbike, according to another UCI source. The UCI issued the communiqué after the stage, referring to article 12.1.040.18, which also said that it fined him 200 Swiss Francs (£120, €140).

Riders regularly take long pulls from their sports directors when grabbing a water bottle out of the team car. The UCI jury typically ignores this sort of assistance and only focuses on the more serious violations.

"I was already off the back on the first climb and then I decided to quit,” Froome told Cycling Weekly. "I was trying to get to the top.”

"I was so close to the end of the Giro d’Italia, but I am still happy with my work.”

He had been suffering from knee problems and complained of this today.

"I have a little issue with my right knee,” he said earlier in the Giro, "there is something pulling on one of the tendons.”

Sky’s sports director, Sean Yates, confirmed that Froome had been suffering from knee problems. He said that he had done a large amount of work in yesterday’s stage to Brescia for Greg Henderson.

"He was trying to get up to the soigneur at the top of the Mortirolo. He knew the Giro was over for him,” Yates told Cycling Weekly.

"Though, we would never encourage our riders to hold onto a motorbike.”

Froome helped Henderson by pulling in the first part of the stage yesterday to Brescia. He finished the day 104th in the overall classification.

Sky brought him to the Giro d’Italia was to help Bradley Wiggins for the overall classification and to help Wiggins prepare for the Tour de France.