The integrity of the entire process was under threat due to major staff shortages, with barely half the volunteers recruited to help run the event reporting for duty and several doping control officers drafted in from overseas walking out after being pushed to breaking point trying to fill the void.

Organisers also admitted that unauthorised individuals had gained access to restricted areas during the drug-testing process, although they denied failing to ensure that anti-doping at the Games was beyond reproach.

One senior figure in the war on drugs with experience of several major events said of the sample-collection system in Rio: “This is by far the worst I’ve seen.”

Rio 2016 began less than three weeks after the publication of a damning report in which Russia was found guilty of state-sponsored doping at the 2014 Winter Olympics.