Ullrich criticised for refusing to break silence

The 39-year-old German won the 1997 Tour de France, winning a total of seven stages in his career, and finished five times as runner-up behind Armstrong before retiring in 2007.

Ullrich was found guilty of violating anti-doping rules by the Court of Arbitration for Sport (CAS) in February 2012 and was retroactively banned for two years from August 2011. All his results since May 2005 were removed.

He was banned for his involvement in the doping program of Spanish doctor Eufemiano Fuentes, who goes on trial in Madrid on Monday.

Rudolf Scharping, president of the German Cycling Federation (BDR), has criticised Ullrich for repeatedly missing the opportunity to speak about his past and to help clean up the sport's image.

"Jan Ullrich has always been given bad advice to not lay his cards on the table," Scharping told magazine Bunte.

"He holds on to it. He has allowed every chance he has had to elapse."

While Armstrong admitted his doping past in an interview with US talk show host Oprah Winfrey earlier this month, Ullrich refuses to break his silence.

"I will certainly not go Armstrong's way and speak in front of millions of people, even if some of them ask me repeatedly and perhaps expect to hear something," Ullrich told magazine Focus.