Cycling Tour de France doping scandalAlmost a month after Jan Ullrich, Ivan Basso and other big-name riders were excluded from the Tour de France on suspicion of doping, the race has been plunged into more scandal with the news the overall winner, Floyd Landis, has returned a positive A sample for testosterone.

The sample was taken after stage 17 of the Tour, the day Landis stunned the cycling world by breaking clear 30 miles into the 125-mile stage and soloing to a spectacular win in Morzine.

He had lost 10 minutes the previous day but his Lazarus-like recovery on the final mountain stage moved him to within 30 seconds of the race leader, Oscar Pereiro of Spain, thus paving the way for his final overall victory.

The International Cycling Union (UCI) had released a statement on Wednesday saying a rider had returned a positive sample but, as per World Anti-Doping Agency (Wada) rules, his identity would not be divulged until the B sample was analysed. Speculation mounted, however, that it might be Landis when he unexpectedly withdrew from a post-Tour criterium at Chaam in The Netherlands later that day.

The American Phonak rider left the hotel at 4.30pm with team manager John Lelangue, and also cancelled a criterium appointment in Denmark scheduled for yesterday. Some of his team-mates said on Wednesday he had withdrawn on medical advice.

Landis (30) rode the Tour with a necrotic hip, the joint essentially disintegrating because of blood supply problems caused by a crash three years ago. He is reportedly allowed use cortisone, a painkiller otherwise banned in cycling, and is due to have a hip replacement within weeks.

But the organisers of both races said they were given no explanation for his withdrawal.

Lelangue has been uncontactable since. But yesterday the Phonak team issued a statement just before 4pm CET, confirming the positive A finding.

"The team management and the rider were both totally surprised by this physiological result," the statement read. "The rider will ask in the upcoming days for the counter-analysis to prove either that this result is coming from a natural process or that this is resulting from a mistake in the confirmation."

Meanwhile, Tour de France director Christian Prudhomme said the "noose is tightening" on drugs cheats.

"If the sample B confirms the sample A then this is terrible," Prudhomme said on French radio. "But we will keep on fighting. We said before the start of the 2006 Tour that we had won a battle but not the war yet.

"We will experience more difficult moments like this one but it proves the noose is tightening on those who still dare to cheat.

"Our will to eradicate doping is indestructible. Soon you will have to be completely crazy to try to cheat again."

In a separate statement issued to journalists, the organisers of the Tour said should the B sample confirm the first result, "all the people who enjoyed the 2006 Tour de France would be overwhelmed by feelings of anger and sadness".

It is likely news of the second analysis will take at least a week. If that again shows an unacceptably high level of testosterone, Landis will face a two-year ban and the Tour de France victory would pass to Pereiro, who finished 57 seconds behind Landis.

Ironically, Pereiro was the one who gained a massive 29 minutes 57 seconds on stage 13 when Landis's team declined to chase, choosing instead to temporarily hand over the yellow jersey and thus avoid having to ride at the front of the bunch in defence of the race lead.

Despite finishing 10th in 2004 and 2005, the Spaniard had lost time in the Pyrenees and was not considered a threat. But he drew motivation from the maillot jaune and held on to yellow until the penultimate day's time trial.

As for Landis, he comes from a strong religious background, his community of Farmersville in Pennsylvania being a Mennonite stronghold. Landis left there years ago to pursue professional cycling - something frowned on by the religion - his positive test is likely to be very big news.

Landis has of course yet to be proven guilty, but if Pereiro is ultimately awarded the race he will be not only one of the biggest outsiders to win the overall category in recent Tour history but also the first Spanish winner since Miguel Indurain in 1995.

It would also be yet another unexpected turn in what was a highly unpredictable and exciting Tour - though few would welcome this final twist, given the damage to the event's reputation.