The Court of Arbitration for Sport (CAS) on Monday ruled that the British Olympic Association's (BOA) lifetime ban on drugs cheats was not in compliance with the World Anti-Doping Agency (WADA) code.
The CAS decision gives the green light to such as British sprinter Dwain Chambers and cyclist David Millar to take part in this summer's London Games should they achieve the qualifying standard.
"The CAS Panel has ruled that the BOA bye-law related to the selection of British athletes for the Olympic Games was not in compliance with the World Anti-doping Code," CAS said in a statement.
"Such decision confirms the jurisprudence established last year in the case between the US Olympic Committee and the International Olympic Committee."
WADA had fought the BOA's policy of imposing life bans for the Olympics arguing that it contravened their own code.
Former European 100m champion Chambers, who won 60m bronze in this year's world indoor event in Istanbul last month, was banned for two years after testing positive for the anabolic steroid THG in 2004.
Millar also served a doping ban in 2004.