On the second day of the doping trial of seven current or former riders of the Cofidis team, Millar said he felt responsible for the team's performance because he was their leader at the time.

"When I saw that when I was bad, the team was terrible, I had the responsibility to become a 'real professional'," Millar said, referring to using the performance-enhancing drugs.

Millar described a trip to Italy in 2001 to stay with team-mate Massimiliano Lelli. Millar said he learned there how to inject EPO through his shoulder, but that the decision to start doping was difficult.

The Scottish rider was banned for two years and stripped of his 2003 world time-trial title after admitting to a French judge that he used the banned blood-boosting hormone.

He has admitted to using EPO three times: once in 2001 and twice in 2003 - including at the 2003 Tour de France. Millar is on trial with nine others. The seven cyclists are charged with "acquiring and possessing banned substances". The other three defendants - a cycling technician, a pharmacist and a former Cofidis trainer - are accused of supplying them with the drugs.

The trial in Nanterre is expected to last a week. The defendants each face up to five years in prison and fines of 75,000 if convicted.

EPO, or erythropoietin, is used by athletes in endurance sports because it increases the oxygen-carrying capacity of the blood, increasing the aerobic respiratory capacity of the muscles.

It is especially effective in multi-stage cycling races because it offsets the decrease in red blood cells that occurs over several weeks of racing.