The controversy around Sir Bradley Wiggins’s use of a banned corticosteroid before three major stage races deepened on Friday night when his former team doctor at the Garmin team, Prentice Steffen, questioned the practice in an interview with the BBC’s Newsnight programme. Both Wiggins and his team at the time, Team Sky, have stated that he was given injections of triamcinolone acetate to treat a legitimate medical condition and that no anti-doping rules were broken.

Steffen was the team doctor at Garmin in 2009 when Wiggins made his breakthrough performance at the Tour de France, finishing fourth overall and subsequently being upgraded to third after Lance Armstrong was found guilty of doping. At that time Wiggins had therapeutic use exemptions permitting the use of an asthma inhaler containing salbutamol, a practice that has since been made legal.

Steffen told Newsnight: “I was surprised to see that there were TUEs documented for intramuscular triamcinolone just before three major events.”

The TUEs, leaked through the hacking website Fancy Bears on 15 September, were issued shortly before the 2011 and 2012 Tours de France – the latter an event that Wiggins won – and the 2013 Giro d’Italia, where he abandoned.

“You do have to think it is kind of coincidental that a big dose of intramuscular long-acting corticosteroids would be needed at that exact time before the most important race of the season,” said Steffen. “I would certainly say now it does not look good, it doesn’t look right from a health or a sporting perspective.”

Steffen worked at the US Postal Service team in the mid-1990s, before Lance Armstrong joined them, and subsequently spoke out against the team and Armstrong over doping. Speaking to Newsnight he called upon cycling’s governing body, the UCI, to act over TUEs, adding: “I would say that Bradley is probably at the bottom of the list to be held personally responsible.

“I think his doctor and his team, to make the decision to apply for that TUE, is questionable and then I think for the UCI or UK cycling or Wada to sign off on that application, all things considered that is the end point where the TUE committee should have looked at that and said, no, this is not acceptable so we are not going to approve it.”

Team Sky said at the time of the leaks – which confirmed that Chris Froome had TUEs in 2013 and 2014 to take tablets containing the corticosteroid prednisolone – that “applications for TUEs have all been managed and recorded in line with the processes put in place by the governing bodies.”

A statement on behalf of Wiggins following the leaks read: “Everyone knows Brad suffers from asthma, his medical treatment is British Cycling and International Cycling Union approved and like all Team GB athletes he follows Wada regulations to the letter.”

Amidst details of Wiggins’s treatment and the development of the allergy, the TUE application forms leaked by Fancy Bears stated that the 2012 Tour winner’s TUEs were issued to treat “life long allergy to pollen nasal congestion/rhinorrhoea, known allergy to grass pollen, sneezing throat irritation, wheezing leading to dysnopnoea eye watering runny nose.”

Newsnight also spoke to the Dane Michael Rasmussen, who has confessed to using a variety of banned drugs during his career plus practices such as blood doping. Asked to comment on Wiggins’s TUEs, Rasmussen said: “Just looking at the drugs and looking at the dates of the injections it looks very much like something that could have happened 10 years ago when I was riding for general classification in the Tour de France. If you look solely at the pattern of TUEs, this looks very suspicious. It’s something that I would do, that I did.”

During his time at the Dutch Rabobank team, Rasmussen worked with Geert Leinders, a Belgian doctor who went on to work at Team Sky on a freelance basis in 2011 and 2012 after the team had dropped an initial policy of not hiring medics with a background in professional cycling.

Both Team Sky and Wiggins’s spokespeople have stated categorically the rider’s TUEs were not requested by Dr Leinders. Wiggins’s representatives did not respond to questions from Newsnight,

Asked to describe the effects of using triamcinolone – which is widely used to treat inflammation of various kinds – both Rasmussen and another self-confessed drug-taker, the Briton David Millar, agreed that it was a potent performance-enhancing substance. Describing the effect of using Kenacort – one of the names under which triamcinolone is sold – and calling for it to be banned, Millar said, “it was the only [drug] you took and three days later you looked different. It’s quite scary because it’s catabolic so it’s eating into you. It felt destructive. It felt powerful.”