On Monday now former Orica-GreenEDGE rider Stuart O'Grady announced his immediate retirement from cycling after riding a record 17th Tour de France amid speculation he would be named in a French Senate inquiry into doping in sport.

Now O’Grady has publicly admitted to doping before the 1998 Tour de France and acknowledged that ‘one horrible mistake’ will smear his entire career. The inquiry, published today, listed one of his urine samples from the '98 Tour as "suspicious".

In an exclusive interview with The Advertiser, O'Grady admitted he sourced the EPO - a blood booster - and administered it without anyone knowing.

Subsequently he carried it with him during the ‘98 Tour, but is adamant he never used it during the race. He said he felt he had no other option and had to use it to survive or be competitive in the race during the sport's dirtiest era.

O'Grady said he destroyed it [the EPO] when the Festina Affair, where riders were booted off the Tour for alleged doping, blew up during the opening week of the now infamous ’98 Tour de France.

O'Grady is unyielding he never used EPO or any other banned substance again.

"Leading into the Tour I made a decision," he said according to the Australian daily The Herald Sun. "I sourced it (EPO) myself, there was no one else involved, it didn't involve the team in any way. I just had to drive over the border and buy it at any pharmacy. The hardest part of all this is I did it for two weeks before the Tour de France. I used extremely cautious amounts because I'd heard a lot of horror stories and did the absolute minimum of what I hoped would get me through. When the Festina Affair happened, I smashed it, got rid of it and that was the last I ever touched it.”

O'Grady, an Olympic gold medallist and Paris-Roubaix champion, was 24 at the time and riding for French team GAN. In the 1998 Tour de France he won Stage 14 and became the second Australian to ever wear the yellow jersey.

O'Grady insists he never cheated after that.

"It was for an extremely small percentage of my entire life," he said. When you start seeing riders getting arrested around you, people being taken to jail, that's all I needed to scare me. I was lucky enough to win a lot of things, they can test my samples from Paris-Roubaix and my Olympic medals for the next thousand years, they're not going to find anything. There is nothing more to hide. I have done everything since then on natural ability.”

Despite his guilt, he never contemplated confessing his mistakes of the past.

"Who in their right mind and the environment we've been in the last couple of years would stand up and be crucified? I guess I just wanted this to go away and the only person I've cheated out of all this is myself, my family and friends.”

A six-time Olympian between 1992 and 2012, O’Grady maintained he could have kept lying in the face of his ‘suspicious' test result.

"There is no B Sample, I could have kept lying, there is nothing but my confession right now," O’Grady said. "I want to close this chapter of my life and have a fresh start. I realise there are going to be consequences but I don't want to stand in front of people anymore and lie.

He said he would take some comfort knowing two of his best mates, Australian Matt White and Scot David Millar, had been through similar circumstances and emerged on the other side.

O’Grady wore the yellow jersey in the 2001 Tour de France, won an Olympic Madison gold medal in 2004 and won the 2007 Paris-Roubaix while allegedly riding clean.

Following O'Gradys confession, his former employer, Orica-GreenEDGE, released the following statement:

“ORICA-GreenEDGE  supports Stuart O’Grady’s decision to step forward and place the findings of the French Senate Report of today into perspective regarding his own past.

"The team would also like to express its support in Stuart as a person and as an advocate for a clean sport. Like the majority of the riders in his generation, he was also exposed to the issues and wrongdoings of the sport and made some wrong choices in that environment.

"We would like to underline that in all of our interactions with Stuart, he has always been extremely clear about the right path for the sport and we believe that certain mistakes in the past shouldn’t be allowed to tarnish his entire career and his integrity as a person.

"ORICA-GreenEDGE is proud to work in a sport that is at the forefront of the fight against doping and that we compete and win as a 100% clean team. The sport has undergone a revolution in setting up the right future for cycling and we consider ourselves one of the strongest advocates for this."