Image 1 of 7 Simon Clarke gives Richie Porte his front wheel (Image credit: Tim de Waele/TDWSport.com) Image 2 of 7 Richie Porte's Twitter page after stage 10 of the Giro d'Italia Image 3 of 7 Simon Clarke gives Richie Porte his front wheel (Image credit: Tim de Waele/TDWSport.com) Image 4 of 7 Simon Clarke provides Richie Porte with help at the Giro d'Italia (Image credit: Tim de Waele/TDWSport.com) Image 5 of 7 Richie Porte (Team Sky) loses time on stage 10 of the Giro d'Italia (Image credit: Bettini Photo) Image 6 of 7 Alberto Contador (Tinkof-Saxo)and Richie Porte (Team Sky) chat during stage 9 (Image credit: Tim de Waele/TDWSport.com) Image 7 of 7 The official decision of the race jury regarding Richie Porte's time penalty (Image credit: Tim de Waele/TDWSport.com)

Richie Porte (Sky) has been docked two minutes by the race jury after he received an illegal wheel change from Orica-GreenEdge's Simon Clarke following his puncture in the closing kilometres of stage 10 of the Giro d'Italia from Civitanova Marche to Forlì.

UCI rule 12.1.040 prohibits "non-regulation assistance to a rider from another team" with a two-minute penalty and a fine of 200 Swiss Francs for a first offence, while a rider risks outright disqualification in the event of a fourth such infraction during the same stage race.

Porte punctured with seven kilometres remaining in Tuesday's stage and lost 47 seconds to the main peloton, despite the wheel offered by Clarke and the assistance later provided by GreenEdge's Michael Matthews during the chase effort.

That deficit and the additional two-minute penalty means that Porte drops to 12th on general classification, and he now lies 3:09 off the maglia rosa of Alberto Contador (Tinkoff-Saxo), having started the day just 22 seconds down in third place.

Shortly after 7.30pm local time, having first summoned Sky manager Dave Brailsford and directeur sportif Dario Cioni to the race permanence to inform them in person, the commissaires issued a statement confirming that Porte had been docked two minutes.

"Clearly there was little to be done, rules are rules, and I think rules have to be respected for the credibility of this sport and, in this case, the credibility of the Giro d'Italia," race director Mauro Vegni told reporters outside the press centre in Forlì on Tuesday evening.

Vegni went on to confirm that Porte and Team Sky had no possibility to appeal the decision. "These are race matters and they are judged by the commissaires and their decision is final," he said.

Porte's illegal wheel change was not captured by television cameras but it appears that the Tasmanian inadvertently provided the commissaires with the evidence they needed to punish infraction by tweeting his thanks to Simon Clarke immediately after the stage, and later retweeting a photograph of his fellow countryman in the act of giving him his front wheel.

"If that's not Aussie mate ship then what is? Punctured and clarkey gave me his front wheel…" Porte wrote.

Vegni dismissed the idea that other teams had alerted the commissaires to the infraction, pointing out that images of the wheel change were circulating on the internet almost as soon as the stage had finished.

"Ragazzi, you know better than me – with the photos that are flying around on the internet these days, you'd struggle to get out of any situation," Vegni said. "Within three minutes there were pictures circulating on the internet of the rider Clarke giving him a wheel."