The British Olympic Association's lifetime ban for drugs cheats has been formally declared unenforceable.
The Court of Arbitration for Sport (CAS) has issued a formal ruling that the BOA's by-law does not comply with the world anti-doping code.
The decision will allow sprinter Dwain Chambers and cyclist David Millar to be selected by Team GB for the London 2012 Games.
CAS said in a statement: "The by-law is a doping sanction and is therefore not in compliance with the WADA code. The CAS confirms the view of the WADA foundation board as indicated in its decision.
"Therefore, the appeal of BOA is rejected, and the decision of the WADA foundation board is confirmed."
The BOA has also been ordered by CAS to "pay all of the costs of the arbitration" - the organisation has already incurred substantial legal costs in hiring top barrister Lord David Pannick to represent them, albeit at reduced rates.
Hugh Robertson, Sports and Olympics Minister, expressed his disappointment at the outcome and called for tougher sanctions for doping offences generally.
Mr Robertson said: "I supported the BOA's position, as our national Olympic committee, in having the autonomy to set its own eligibility criteria for Team GB athletes.
"I accept this ruling from the Court of Arbitration for Sport but it is very disappointing."
UK Athletics confirmed that any athletes such as Chambers who had been affected by the lifetime ban would now be eligible for selection.