Dunwoody was champion jockey three times

He rode 1,699 winners in Britain - plus 172 in Ireland and 10 abroad - in 16 years in the saddle before a neck injury forced him to retire in 1999.

The Ulsterman, who is now 41, harboured dreams of a return after a successful neck operation in September.

But tests showed his neck was more arthritic than when he retired, ruling out a possible comeback.

He said: "Unfortunately, I will not be taking AP McCoy (current champion jockey) on at Cheltenham next year.

"I am disappointed but it was a bit of a pipe dream. I am fitter and healthier now than when I retired.

"I was hoping for the impossible a little bit anyway but had my neck looked good and the X-rays looked good then I certainly would have come back.

"I'm 41 and Conor O'Dwyer and Carl Llewellyn are riding as well as ever so there was no reason not to come back on account of my age."

Dunwoody now hopes to concentrate on motivational speaking and television work.