Spanish cyclist Alberto Contador on Monday received a two-year ban for doping during the 2010 Tour de France and was stripped of his victory in the race.
The Court of Arbitration for Sport (CAS) said Contador's suspension runs through to August 6, 2012, which means that the Spaniard loses his 2010 Tour victory and will be unable to take part in this year's race.
Contador tested positive for the banned anabolic agent clenbuterol, but he was subsequently cleared by the Spanish Cycling Federation (RFEC) in February 2011, prompting the World Anti-Doping Agency (WADA) and the International Cycling Union (UCI) to appeal the decision to CAS.
The 29-year-old Spaniard claimed he had ingested the banned substance by eating a contaminated steak, an explanation which satisfied the RFEC but which failed to pass muster with the UCI and WADA.
"CAS has partially upheld the appeals filed by WADA and the UCI and has found Alberto Contador guilty of a doping offence," CAS said in a statement.
"As a consequence, Alberto Contador is sanctioned with a two-year period of ineligibility starting retroactively on 25 January 2011, minus the period of the provisional suspension served in 2010-2011 (5 months and 19 days). The suspension should therefore come to an end on 5 August 2012."
CAS added that the "presence of clenbuterol was more likely caused by the ingestion of a contaminated food supplement" than by contaminated meat.
Apart from losing his 2010 Tour de France title, the verdict means that Contador is stripped of all his wins in 2011, which include the Giro d'Italia.
It also comes as a further body blow to the sport of cycling which has been wracked by doping offences over the last 15 years - particularly involving the Tour de France, the toughest and most prestigious race in the world.
Contador has 30 days to lodge an appeal with the Swiss Federal Court. There was no immediate reaction from the cyclist.
The UCI said that though it derived no satisfaction from the verdict, it "welcomed the news as the end of a long-running affair that has been extremely painful for cycling".
"This is a sad day for our sport. Some may think of it as a victory, but that is not at all the case," said UCI President Pat McQuaid.
"There are no winners when it comes to the issue of doping - every case, irrespective of its characteristics, is always a case too many."
Contador's win in 2010 was his third in the Tour de France and under UCI rules his suspension means he would forfeit the victory to Andy Schleck of Luxembourg, who finished as runner-up.
Belgian cycling legend Eddy Merckx said he was "shocked and disgusted" by the CAS ruling.
"Once again it's cycling that pays the price," Merckx told AFP. "It's an excessive punishment. It's bad for everybody, for the reputation of cycling, for sponsors.
"It's as if someone wants to kill cycling. They took two years to make this ruling. It's that that is not good."
Merckx added: "I'm neither an expert nor doctor. But I'm really waiting for the explanations of these experts. It's only in cycling that we seek to detect the tiniest quantities.
"I'd like that we do the same thing in other sports.
"If there'd been clear proof to prove Contador had doped, he would have been immediately suspended. We wouldn't have waited for two years," said the five-time Tour de France winner, adding that Contador's defence strategy "had not been good".