Just last month Bradley Wiggins, the first British man to win the Tour de France, was basking in the glory of becoming the country’s most decorated Olympian at another glittering Games for Britain’s cyclists.

Now he faces a fight for his reputation as some of his hitherto most loyal supporters echo questions around his record on performance-enhancing drugs arising from a Russian-led hacking effort into the World Anti-Doping Agency (Wada) database.

The questions surround the use of medical certificates to allow athletes to take otherwise banned substances for pre-existing conditions, and they are not particularly new. But the specificity and ferocity with which they are being asked in the wake of the Russian leak is new.

Wiggins has been forced to deny that the controversial Belgian doctor Geert Leinders was involved in his obtaining so-called therapeutic use exemptions (TUE), after details of the TUEs granted to both he and fellow Tour de France winner, Chris Froome, were leaked late on Wednesday night. The leak detailed three TUEs obtained by Wiggins for the treatment of asthma and allergies between 2011 and 2013 – each before his major target race for that season.

Wiggins has also had to clarify apparent inconsistencies between what he wrote in 2012 about the use of needles and the details that have emerged via the Fancy Bears hackers.

Leinders was a Team Sky doctor between 2011-2012 – Wiggins won the Tour de France in the latter year – who was later banned for life for doping offences committed during a previous stint at the tainted Rabobank cycling team between 2001-2009.

Since the formation of Team Sky, originally envisioned as a professional road racing offshoot of British Cycling’s successful Olympic operation, the longstanding team principal, Dave Brailsford, has preached a loud anti-doping message.

After Froome’s Tour de France victory last year, achieved amid a toxic atmosphere of suspicion and friction, Brailsford likened those accusing Team Sky of cheating to hunting fruitlessly for the Loch Ness monster.

The stated aims of the team when it was launched in 2009 were to win the Tour de France with a British rider within five years and to do so as a demonstrably clean team. As though on a crusade to rescue cycling’s reputation in the wake of the near-fatal damage of the Lance Armstrong years, Team Sky outlined an evangelically “zero tolerance” policy to doping.

This extended not only to insisting it would not employ anyone with a known doping past but to inviting David Walsh, the Sunday Times journalist who did much to bring down Armstrong, to live with the team under an open-door policy.

Even as the difficulties of working within a sport in which doping became the price of entry became clear, such as the ban for Leinders and a two-year doping suspension for rider Jonathan Tiernan-Locke, Walsh has hitherto seen no cause for concern.

But under the headline It looks bad, Brad, a disappointed Walsh concluded this week in the Sunday Times: “The team that wanted to be seen as whiter than white had been dealing in shades of grey. What they did was legal, but it wasn’t right.”

Walsh also suggests that a 2012 injection of triamcinolone, ahead of Wiggins’s historic Tour victory, was given as a preventive measure rather than to treat existing symptoms.

There is no suggestion Wiggins did anything to break anti-doping regulations. But those shades of grey are likely to be pored over even more closely in the coming days and weeks as the Fancy Bears release even more confidential medical records hacked from the Wada database during the Rio Olympics.

The problem for Wiggins, for Brailsford, for Team Sky and even for British Cycling as a whole is that, having insisted so publicly and so vehemently they would be whiter than white, anything less starts to look like hypocrisy.

Ross Tucker, a respected South African sports scientist who is hawkish on whether TUEs should be banned altogether, said on Twitter: “I’d say Sky have been exposed on principle (their stated ‘line’ that wouldn’t be crossed) & promise.”

Wiggins, who will retire later this year, memorably railed against his doubters during his 2012 Tour victory and immediately afterwards wrote an autobiography in which he did not mention his TUEs. Not only that, he went further by outlining his aversion to needles.

“British Cycling have always had a no needle policy, it’s been a mainstay of theirs; so it’s something I’ve grown up with as a bike rider,” he wrote.

“In British cycling culture, at the word ‘needle’ – or the sight of one – you go, ‘Oh shit’. It’s a complete taboo … I’ve never had an injection, apart from I’ve had my vaccinations and on occasion I’ve been put on a drip, when I’ve come down with diarrhoea or something.”

On Saturday, a spokesman for Wiggins said that the mention of needles referred to the practice of intravenous injections. The spokesman went on to clarify that the triamcinolone injection that Wiggins received was an intramuscular injection.

It must be repeated that there is no evidence that Wiggins or Sky did anything that was not within the rules. And, also, that the rationale behind TUEs is obvious in terms of allowing athletes with pre-existing medical conditions to compete.

“If the anti-doping community wishes to change the international standard [for allowing TUEs] then that could be done. But there are wide implications,” said Craig Reedie, the Wada president, on Sunday.

Wada has repeatedly insisted that medical confidentiality dictates that TUE applications should remain private and points to the robustness and independence of the process. But on the other side of the argument, difficult questions over the use of TUEs to boost performance by unscrupulous coaches and doctors persist.

Appearing on the BBC’s Sportsweek programme on Sunday, the respiratory expert Dr John Dickinson of the University of Kent, said: “The way the rules are, it allows for that grey zone. It allows for that 1per cent of athletes with the help of a medical doctor to look at the system and say: ‘You know what, we can get you that drug.’ There is no clear evidence, but the rules can allow that to happen.”

The renewed speculation around Wiggins and other high-profile western athletes is exactly what the Russian hackers linked to the Fancy Bears leak wanted to achieve. Their aim is to set up a dynamic where the often legitimate use of TUEs muddies the waters to the extent that some start to equate it with the large-scale, state-sponsored cheating uncovered over the past year that almost resulted in Russia being banned from the Rio Games. That the two issues should not be conflated should not make either any less valid.

Jonathan Vaughters, a former American cyclist who now runs his own team, suggested a way forward that is being advocated increasingly loudly. “Want a good solution for TUEs? Make it compulsory to publicly disclose all TUEs,” he said. “Any athlete would think twice unless they really needed it.”

(Guardian service)