Thorpe also admitted feeling intensity from outside to continue swimming but said he did not have the motivation to continue within himself . "It would be dishonest to myself, and to everyone else, if I were to continue on that basis," he said. "I've reached all the dizzy heights of this sport - for all of that I'm extremely appreciative."

Thorpe did not completely rule out a future comeback, but said: "I don't see myself competing again, it won't happen. I won't rule anything out, I never rule anything out, but it just won't happen."

Tributes were quick to flow in for Thorpe, with Australian Olympic Committee president John Coates saying: "He's certainly an out-and-out champion. He is our most successful Olympian ever. He has and I'm sure will remain an inspiration to many children. People are saying was he under too much pressure, but you've got to remember he went to two Olympics and 24 is old for a swimmer.

"Not too many of them, particularly the males, go past that. He's had a very long and distinguished career in world swimming.”

Prime Minister John Howard said Thorpe’s great performances would be long remembered by millions of Australians, while Opposition leader Kim Beazley said:
"He has been a terrific swimmer, a terrific athletic example to Australians for - in a man so young - a very lengthy period of time. He's our greatest Olympian and he will be missed."

Grant Hackett, probably Thorpe’s greatest rival, admitted he was shocked by Thorpe’s announcement. "I think it still seems a little bit surreal," he said. "I am shocked by the decision. I thought he'd be pulling out of the world championships but not, as he put it, discontinuing from the sport.”

Hackett, a two-time 1500-metres Olympic champion, added: "It's an incredibly sad day not just for Australian swimming but for world swimming. "They've lost one of their great athletes and a guy who has brought so much to the sport. Swimming's always been big at the Olympics and world championships but he made it bigger than ever.”

"He was able to really bring the sport of swimming into the limelight with incredible performances. There's no words to describe right now how much he'll be missed by the sport in general."

Thorpe started swimming at age five, and at 14 became the youngest male to represent the Australian senior swim team when he competed at the Pan Pacific Championships in Japan in 1997. As his career took off, Thorpe became a genuine superstar in Japan, his popularity in the Land of the Rising Sun equalling or even surpassing that of his homeland.

In 1998, he won the first of his 11 World Championships, taking gold in what would prove to be his pet event, the 400 metres, in Perth. That victory made him the youngest ever male world champion.

Thorpe later broke the first of his 13 individual world records, setting a new short course record for the 400 metres. He claimed his first world mark in the 50-metre pool in 1999, again in the 400 in Sydney, smashing the five-year-old mark of fellow Australian Kieran Perkins by two seconds.

Sydney was againe the scene of glory for Thorpe 12 months later when, on the first night of swimming competition at the 2000 Olympics, he produced two of the great swims in Australian Olympic history. First he broke the world 400-metres record and only 80 minutes later anchored Australia to a last-gasp victory over the Americans in the 4x100m freestyle. It was the first time in Olympic history that the USA had not won the event.

The 2001 World Championships in Fukuoka, Japan would become the Ian Thorpe show, with the Australian claiming an incredible six gold medals, in the process breaking his own world records in the 100, 200, 400 and 800metres, as well as being a member of Australia’s 4x200m relay which also set a new world mark. Thorpe’s world-record time in the 200 metres of 1:44.06 in Fukuoka still stands, as does Australia’s relay record of 7:04.66.

Thorpe went on to break the 400-metres world record one final time in 2002 during the Commonwealth Games in Manchester. His time of 3:40.08 has yet to be bettered. He went on to win six gold medals in Manchester..

Thorpe’s final major meet was the Athens Olympics in 2004, where he successfully defended his 400-metre crown, while beating fierce rival Pieter van den Hoogenband to win gold in the 200.

Thorpe had also intended to take 12 months away from the pool after Athens, missing the 2005 World Championships in Montreal in the process. But the road back to the top was not to be easy one for the man known as “Thorpedo”, injury and illness setbacks preventing him from reaching peak fitness. He was set for a return to international competition in March this year for the Commonwealth Games in Melbourne, only for a bout of glandular fever to derail his comeback.

It was during his recovery from this illness that Thorpe began to lose the desire that saw him reach such great heights. The stress of constantly being in the public eye and the long dreary hours of training finally wore down on the man in a way that few, if any of his opponents, could.