Dwain Chambers will confess to anti-doping chiefs tomorrow that he was on an astonishing cocktail of seven banned drugs in 2003.

The British sprinter tested positive for the designer steroid THG in August of that year, and received a two-year ban. But it has now been revealed he was also taking human growth hormone, the blood-boosting drug EPO, insulin, a testosterone/epitestosterone cream, a drug called modafinil used to promote alertness, and finally liothryonine, a synthetic form of thyroid hormone.

Chambers is meeting John Scott, UK Sport’s anti-doping chief, tomorrow as part of his campaign to come clean, and hope to gain a place in the British Olympic team.

He will provide Scott with an explosive letter written by Victor Conte, his American drugs supplier, detailing his actual drugs use. Conte’s letter has been obtained by BBC Sport, and he told the broadcaster: “This was the most sophisticated doping programme in the history of sport.”

The programme was put together ahead of Chambers competing at the 2003 athletics World Championships, though he performed disappointingly at that event.

Nick Collins, Chambers' lawyer, said: “I can confirm we are meeting John Scott. The intention is to open up a dialogue with UK Sport and to be as helpful as possible in their fight against doping. We will be taking the letter with us and discussing its contents.”

The letter from Conte, which reads like a cheat’s charter, reveals most of Chambers’ drugs were used in cycles of three weeks on, one week off during the winter training period in conjunction with an intense weight-lifting programme.

Chambers has recently been released by rugby league side Castleford after a month’s trial and has returned to sprint training. He needs to overturn the British Olympic Association’s lifetime ban if he is to be able to compete at the Beijing Games.