The 35-year-old, from Northern Ireland, rode 1,699 winners in Britain, becoming champion jockey three times and was awarded the MBE in June 1993.

Dunwoody has suffered problems in his neck and right arm which he puts down to nerve damage from the persistent battering he has taken while racing more than 10,000 times.

He has not ridden since August and after speaking to medical experts in Britain, Ireland and the United States he was advised to retire.

In a statement, he said: "It is with regret that due to medical advice, I am to retire from race-riding.

"A neck injury sustained at C5-C6 has led to loss of strength in my right arm.

"This first became apparent in a fall in May 1998 and although it recovered, it was again weakened in a fall at Edinburgh in January this year.

"This was compounded by further falls during the summer, the last being at Perth in August.

"It is sad I leave behind some great memories and certainly not from just the big days. I'm going to miss the weighing room very much - the lads are the best bunch of people you could ever wish to work with."

Honours flood in

Richard Dunwoody's friends and rivals in the saddle were quick to praise him upon hearing the news.

Trainer David Nicholson, for whom Dunwoody rode Charter Party to win the Tote Cheltenham Gold Cup in 1988, said: "I am not surprised, I am sorry he has had to retire, but I am delighted he is going out at the top.

Former jumps jockey John Francome, third behind Dunwoody in the all-time winners list, said: "I rode against him a great many times of course and his retirement is sad for spectators.

"He was the one man who could give Tony McCoy a run for his money.

"He was like 'Scu' (Peter Scudamore), very dedicated but perhaps a little bit more polished.

"He made bad horses look good and every day he was at his best, never any highs or lows. It is better for him to go at the top rather than go downhill and perhaps get a serious injury."