In mid-2000 the late Terry Gathercole, the head of Swimming Australia, organised for Thorpe to talk to the high-profile, openly-gay solicitor John Marsden.

Mr Marsden told Fairfax Media at the time that he had organised a conference call with Canadian swimmer Mark Tewksbury, who had come out six years after he won the gold medal and broke the world record for the 100-metre backstroke at the 1992 Olympics.

Tewksbury said yesterday that he recalled speaking to Mr Marsden but that Thorpe’s identity was not disclosed. "I always questioned his sexuality but his name was never revealed to me," Tewksbury said.

Speaking from Canada, Tewksbury said that he had come out in 1998 because mere rumours that he was gay caused him to lose a "six-figure speaking contract".

"I knew when I did it, there was a chance I could lose everything … that was the reality," he said of the negative attitude of sponsors towards gay athletes at the time.

Tewksbury said he shared how "tough" his decision was, but added it was also liberating. "It was all worth it," Tewksbury said. "It’s much more important than anything else."

The day after the conversation with Tewksbury, Mr Marsden told the Herald that the Canadian swimmer did not try to dissuade Thorpe from coming out but made sure he was aware of the financial consequences.

Mr Marsden said Thorpe weighed up the advice and decided to postpone the announcement until later in his swimming career.

Thorpe's management has not responded to a request for comment.

Tewksbury is relieved that Thorpe no longer feels like he has to live in the closet.

"As long as you are keeping this big secret and living a double life, that’s a huge burden to bear," he said.

"This is a big step for Ian, it takes a lifetime to catch up, but it’s a really great first step."

Olympic gold medallist and gay Australian diver, Matthew Mitcham, agreed.

"I think it's wonderful that he feels like he’s in a place now where he can talk about it," Mitcham said. "He may not have been in a place where it was safe for him to do this before."

Tewksbury believes that Thorpe is on a different level to any other openly gay athlete.

"It was always the question of who was going to be the really big star," he said. "Ian is an icon, Ian is the star."

Mitcham said: "There is no precedent, not on this scale. It must have been a very harrowing ordeal.

"It took him 15 years to change his answer [to the question of his sexuality], which is a perfect indicator of his struggle."

Mitcham said sponsorship commitments would have weighed heavily on any athlete deciding whether to go public with their sexuality; the stereotypes and the stigma are well known. "That's why we need high-profile gay athletes, to prove the stereotype wrong," he said. "Thorpe is about as high profile as it gets."