The start of the Olympics was in danger of being plunged into chaos by the Russian doping crisis on Sunday night after the International Olympic Committee admitted a final ruling on the expulsion of the country’s athletes may not be made until hours before Friday’s opening ceremony.

An outbreak of appeals against bans already imposed on competitors from the rogue nation also threatened to derail the kick-off of Rio 2016, the build-up to which has been marred by the fallout from arguably the worst drugs scandal in history.

The IOC’s president insisted on Sunday it was not to blame for the unprecedented shambles, declaring it the fault of the World Anti-Doping Agency.