Sir Chris Hoy: 'Question marks' hanging over Sir Bradley Wiggins

Hoy, who has always been a great supporter of Wiggins, spoke for the first time about revelations that the Olympic hero received intra-muscular injections of a performance-enhancing drug ahead of major races in 2011, 2012, and 2013.

Speaking to BBC Radio 2, Hoy said: He definitely has to answer questions – otherwise there’ll always be a question mark hanging over him.

"It’s not been a great few weeks for Team Sky or for Bradley in particular… it’s up to Bradley, he needs to clear his name, I’m sure and explain what the situation was.”

Wiggins’ TUE certificates, alongside those of numerous other athletes, were leaked by hacking group Fancy Bears in September. The certificates showed that Wiggins – a lifelong asthma sufferer - was administered an intra-muscular corticosteroid triamcinolone with permission from the anti-doping authorities because of pollen allergies, days ahead of the 2012 Tour de France, which he went on to win.

The drug in question, which is an anti-inflammatory, has been used by athletes as a performance-enhancer, though Wiggins maintains that use of the drug merely put him on a “level playing field” with other competitors.

Though there is no suggestion that Wiggins broke the rules, the case has raised issues about the TUE system and the potential for it's abuse.

Hoy said: "TUEs are important for the reason that they’re to protect athletes’ health.

"Ninety-nine point nine per cent of athletes have them for a very good reason – without them, you’re going to put your health at risk. So it’s about having TUEs for the right reason but not abusing the system.”