Victor Conte, the brains behind Balco, the Californian laboratory that was exposed as one of the most comprehensive doping operations in sports history, is out of prison, back in business and working with professional athletes again. In his first newspaper interview since his release from prison last year, Conte told The Times that he has a group of ten elite sports people whom he is advising and supplying as their specialist in nutritional supplements.

Conte is working from the same building in Burlingame where Balco – the Bay Area Laboratory Cooperative – was based and is running a nutritional supplements business called SNAC (Scientific Nutrition for Advanced Conditioning). Life appears to be so much like before that occasionally he even posts a picture of Barry Bonds, the baseball player, on the homepage of the SNAC website. There is one essential difference now, Conte said. “All ten are clean. I will never even discuss doping with them. Never again. That is a past life for me.”

From the outside it appears astonishing that any athlete would risk association with Conte, even if he is going straight. But he, of course, tells it differently. “These ten I’m with – I’m talking people who have won medals at World Championships and other elite people who have won at the same level in other sports – it’s best for them and me to keep their names out of it,” he said. “I’m proud to still have the trust of a lot of people like this.”

Conte said that he will not dope any more, but that is not because he believes that doping is wrong. No, the reason he will not dope is because of the pain that the notoriety and the four-month prison sentence caused his family. He did not find it too bad. “Federal prison camp is like being on a cruise,” he said. “Only you can’t get off. They have Starbucks, the food is good. For me it was like vacation, for my family it was like hell.”

As one of the world’s greatest doping experts, though, he has knowledge that few are prepared to share – and his view of world sport and the prevalence of doping in athletics in particular is deeply alarming. “It’s very difficult to reach a final of a world [athletics] event clean,” he said. “The overwhelming majority haven’t.”

What percentage have cheated to get there? “Closer to 80 per cent than 60,” Conte said.

He cites a final from a recent world athletics event from which three of the eight competitors were subsequently implicated in doping. “There are two others in that event that I provided with performance-enhancing substances,” he said. “So I already know that five of the eight were on it.”

Overall, how prevalent is doping in athletics? “I believe that of the 10,000 athletes that competed in Sydney [in the 2000 Olympics], at least half of them had used some sort of performance-enhancing substances,” Conte said. “They have linked 15 people to me. My question is, where did the other 4,985 people get their stuff?”

The way he tells it, you half-expect that he knows the answer.

Running a successful doping operation, he said, “was about much more than developing drugs and methods. It was a network of people; to win any war, you need intelligence. I had access to information from people that were inside the labs. I would find out what they were doing in terms of testing designer steroids.

“I know of an accredited lab in Europe that had an employee who was coming in at night and doing prescreening of urine samples for athletes – to help these athletes beat tests and monitor clearing times. What I’m saying is, it’s not about the drugs, it’s about knowing who’s doing what, when and where.”

This intelligence network broke down when his athletes simply got too good. “This whole Balco thing [its downfall] was about athletes that had worked with me before, went to another camp, told them exactly what we were doing and then dropped Kelli White [a former client] in it,” he said. “Otherwise Kelli would never have tested for Modafinil [after the women’s 100 metres final of the 2003 World Championships in Paris].

“It was a complete inside job. Believe me, the doping officials would never have figured that out themselves. This was like East-West Coast gang warfare where they did a drive-by shooting. They realised that they couldn’t compete on the track and the only way for them to win was to turn me in.”

It is established fact that Trevor Graham, the former coach of Marion Jones and Tim Montgomery, the United States sprinters, sent to the authorities a syringe of Conte’s “magic potion”, THG (tetrahy-drogestrinone). Conte said that this was only after his relationship with the three had ended in 2001. The next year, Montgomery broke the world 100 metres record.

“Montgomery had stockpiled the stuff he received from me, so he was able to walk away knowing he had the stuff and knew the protocol to use it for another year,” Conte said. “But having terminated my relationship with Trevor, Marion and Tim, a collusion developed and in 2002 they sent it to all the accredited laboratories. It then took them a year to develop the test.”

It was the rise of one of his new athletes, Dwain Chambers, the Briton, Conte said, that worried his former clients and they turned on him. “Dwain is a great guy who got caught up in something he shouldn’t have been in,” Conte said. “But he, like me, realised that this [doping] is what goes on, that these are the rules. He’s had tremendous damage done to his life because of it.”

But even when the whistle had been blown on Balco, according to Conte, he would have had every reason to have believed that it was not the end of the operation.

“I have direct knowledge from Olympic governing body officials from the US who have told me about a number of cover-ups of positive tests,” he said. “These are cover-ups of people who won gold medals for the US. Even some of the athletes I personally worked with – I would get calls from the officials and they would tell me, ‘Your boy tested positive.’ And a few days later I would get a call and they’d say, ‘We’ve decided to cover this up.’ ” Alarming as this all sounds, it works in Conte’s favour to tell it this way. “I’m one of the only guys telling the truth,” he said. But it works for him because it justifies everything that Balco was about. “It wasn’t me who created an unlevel playing field,” he said. “The ineptness of the antidoping programmes contribute to the use-or-lose mentality that athletes are almost forced into. Its rampant use makes it virtually impossible for an athlete not using performance-enhancing substances at the top level.

“For many years, my business was only supplements that were legal. But I learnt what the real rules were about and then I made a decision. I knew athletes were buying these substances in dark alleys, from the trunks of cars, behind gyms. They were going to do it with or without my help. I felt I could help them to do it in a more safe manner.

“My message is to the parents of the young athletes of the future: the use of performance enhancing drugs at the elite level is rampant. If you don’t want your son or daughter to take drugs, then you need to steer them in other directions. Because at some point, they’ll get to the level where they are told they have no choice but to use them.

“Am I saying that doping is right? No, I’m not. I’m just saying that’s the way it is.”