AN anti-doping investigation has uncovered evidence that Russian competitors’ urine samples from the 2014 Winter Olympics in Sochi were tampered with in a cover-up of illegal drug use.

An independent commission set up by the Word Anti-Doping Agency (Wada) found scratch marks on the necks of sample bottles consistent with claims that samples were swapped for “clean” urine. Its two-month investigation found evidence of “state-directed” doping throughout Russian Olympic sport.

Chairman Richard McLaren delivered three main findings – that doped samples “disappeared” from the anti-doping laboratory in Moscow, that they were swapped with clean samples at the laboratory for the Sochi Games, and that these plans were directed by the Russian sports ministry.

The Canadian law professor said he had “unwavering confidence” in his findings. Wada last night led calls for Russia’s Olympic track and field ban to be extended to the entire Rio Games.

The investigation came after the former director of Moscow’s anti-doping laboratory, Grigory Rodchenkov, described in a New York Times interview an elaborate plan to ensure Russian success at Sochi.

Rodchenkov, who was sacked after the first Wada-funded investigation into doping in Russian athletics last year, has been in hiding in the United States since the interview was published and has been branded a “criminal” and a “traitor” by senior Russian figures. But McLaren’s “intense” investigation completely vind- icates Rodchenkov’s claims.

McLaren said his team used forensic analysis, seized computers, studied data and performed extra tests on stored samples from the Games and other major events. Rodchenkov claimed the Russian secret service (FSB) had worked out how to open and re-seal the supposedly tamper-proof bottles that are used for storing urine samples, so that the contents could be replaced.

In an effort to prove this allegation, McLaren, who was also involved in the first investigation into Russian doping, sent a random amount of samples from “protected Russian athletes” at Sochi stored by the anti-doping laboratory in Lausanne to a lab in London to see if they had scratch marks around the necks of the bottles that would indicate they had been manipulated.

McLaren said “100 per cent of the bottles had been scratched” although added that this would “not have been visible to the untrained eye”. He said had “unwavering confidence” in the 103-page report’s findings.

Breaking down his three main findings, McLaren said the “disappearing sample methodology” involved Rodchenkov’s lab, the Russian anti-doping agency (Rusada), the Center of Sports Preparation of National Teams of Russia (CSP) and the Russian sports ministry.

The report says Rodchenkov would receive a “save” or “quarantine” code message from the ministry to determine whether he simply lost an athlete’s sample or correctly processed it. In total, 643 samples from doped athletes vanished between 2012 and 2015.

McLaren’s report directly names deputy sports minister Yuri Nagornykh and chief anti-doping advisor Natalia Zhelanova as being central to the scheme, but also says it was “inconceivable” that sports minister Vitaly Mutko, who also runs Russian football and sits on Fifa’s council, was unaware of what was going on.

The second finding, which McLaren refers to as the “sample swapping methodology”, relates to the clandestine operation that Rodchenkov ran with the FSB at Sochi’s anti-doping laboratory. This involved smuggling Russian samples which would almost certainly have failed a drugs test out of the lab through a “mouse hole” in the wall and swapping them for samples with clean urine stored in a secret room on the other side of the wall.

Rodchenkov would sometimes add table salt to the urine to hide the manipulation and then an FSB agent would reseal the bottle.

The exiled Russian told the New York Times he had done this for “dozens of athletes”, including at least 15 medal winners in Sochi, where Russia topped the medal table.

Wada president Sir Craig Reedie reacted to McLaren’s findings with something close to horror, such is the scale and scope of Russia’s doping conspiracy.

The Scot, who is also an International Olympic Committee vice-president, said last night: “Wada are calling on the sports movement to impose the strongest possible measures to protect clean sport for Rio 2016 and beyond.

IOC president Thomas Bach, who has called for an urgent meeting of his executive board today, said: “The findings of the report show a shocking and unprecedented attack on the integrity of sport and on the Olympic Games.”