The teak-tough Irishman suffered serious neck and knee ligament damage after a fall from L'Ami in the John Smith's Grand National in April.

Fitzgerald had previously broken his neck in a fall at Market Rasen in 2005 and has now been advised not to return to race-riding.

His highs included National glory on Rough Quest and legendary commentator O'Sullevan, who called that race in 1996, said: "I'm sure it's a wise decision.

"I can't think of anyone who could have faced what he had to face with greater courage and resolution.

"I have unqualified admiration for him, both as a jockey and particularly as an individual.

"Happily he won't be missed too much as he will stay with us in the media and continue to enlighten us with his comments on the game and horses in general.

"I think he has been and remains a credit to the game and I suppose my most lasting memory of his career was his victory on Rough Quest as I happened to call the race.

"His memorable post-race comment, and I will leave it at that, will also last long in the memory.

"He has always been a breath of fresh air to the game and he is just a splendid man.

"I couldn't commend him higher and I could not possibly wish him more good fortune."

Fitzgerald said: "It is hard to swallow when you finally realise it is the end.

"I suppose in many ways I'm lucky really.

"I smashed four vertebrae in my neck from the C6 up to C3, they were fairly badly damaged and I was lucky first of all to go to Royal Liverpool University Hospital and have a couple of discs removed and have the whole thing stabilised because two of them had penetrated my spinal cord and I was very lucky.

"Unfortunately in this situation I have got to listen to the experts."

Fitzgerald, who has already done a lot of work for At The Races, is now considering furthering his career in the media sphere.

"The media work is something I feel comfortable doing and it's something I enjoy doing and I always want to be involved in racing," he said.

Fitzgerald partnered well over 1,000 winners in a 20-year career, including 762 for trainer Nicky Henderson, and is one of an elite band to win both the National and the Cheltenham Gold Cup (on See More Business in 1999).

"I've been so lucky to be associated with a lot of good horses," he added.

"Rough Quest was one of the first of the big horses as I won the Grand National on him in 1996 and the William Hill Chase."