Riis admitted he was using EPO when he won the Tour in 1996

Riis became the first Tour winner to admit doping when he said he had taken illegal blood-booster EPO between 1993 and 1998.

"I purchased it myself. It was part of everyday life as a rider," he said.

The International Cycling Union (UCI) urged Riis "to return his yellow jersey, the symbol of his victory".

Cycling has long been hit by doping allegations but in the past week a number of the sport's stars have admitted doping.

There is now a strong desire among the majority of people in the cycling world to change things UCI president Pat McQuaid

Riis's admission came the day after former Telekom team-mates Erik Zabel and Rolf Aldag also admitted using EPO, while 2006 Giro d'Italia winner Ivan Basso is facing a 21-month ban after admitting attempted doping.

UCI president Pat McQuaid says he believes cycling has reached a turning point.

"Although the past and the present may confront us with difficult issues, there is now a strong desire among the majority of people in the cycling world to change things," he said in the statement.

"Cycling is currently in a crucial period of self-criticism, a necessary step if we are to move on to a healthier situation.

"The process underway must lead us to a new kind of cycling, with a new spirit among the riders, managers, sporting directors and team doctors who have learned from the all-too-often negative experiences of the past.

"I am very optimistic and urge all those involved in our sport to co-operate.