Dwain Chambers, the British sprinter, and David Millar, Scottish cyclist, have been cleared to compete in this year's London Olympics after the British Olympic Association's (BOA) lifetime Games ban on drug offenders was overturned by the Court of Arbitration for Sport (CAS) on Monday.

The BOA asked CAS to mediate after the World Anti-Doping Agency (WADA) ruled the life ban did not comply with its global doping code which provides for a maximum two-year ban for a first offence.

"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 on its website.

"Such decision confirms the jurisprudence established last year in the case between the US Olympic Committee and the International Olympic Committee."

The BOA described the decision as a "hollow victory" for WADA.

"The BOA are clearly very disappointed in the outcome," BOA chairman Colin Moynihan said.

"No doubt for athletes, for coaches and administrators and others in international sport who want to see greater progress in the fight against doping, this will be seen as a hollow victory for WADA."

In October 2003, Chambers received a two-year athletics ban and a ban from the Olympics for life for using THG, a banned performance-enhancing substance.

Millar was banned from the Games after police found empty phials of Eprex, a brand of the blood-boosting drug EPO, at his apartment in Paris.