The British Olympic Association have lost a court case to keep their lifetime ban for drugs cheats.

The Court of Arbitration for Sport (CAS) will announce on Monday their decision that the BOA's bylaw does not comply with the World Anti-Doping Agency's (WADA) global code, sources with knowledge of the case have confirmed to the Press Association.

The outcome means sprinter Dwain Chambers and cyclist David Millar will have their lifetime bans lifted to allow their selection for Team GB for the London 2012 Games.

CAS rulings are not always cut and dried in favour of a single party, but it is understood this ruling is unequivocally in favour of WADA.

The BOA's response will be to accept the defeat, with the first action to formally remove the bylaw at a full board meeting. That will then open the way to allowing UK Athletics to select Chambers in July, and British Cycling to do the same with Millar in June.

The two athletes had been subject to the lifetime rule for after being banned for doping offences eight years ago. Shot-putter Carl Myerscough would also be eligible for selection.

The BOA will now concentrate on their proposals to change WADA's global code on doping. They have proposed a minimum four-year ban for a first serious doping offence, including missing one Olympics, with national Olympic committees having the autonomy to have tougher sanctions if they so choose including a lifetime ban.

Any such agreement would not come before the London Games however so would not affect Chambers' and Millar's participation.

Most anti-doping experts believe that it is more likely that WADA will agree to change the new code to increase the length of a ban for a serious offence, but will stop short of allowing different Olympic committees to have different sanctions.

Chambers tested positive for the designer steroid THG in 2003 and was banned for two years. Millar admitted to taking the blood-boosting agent EPO and he too was banned for two years.