Jockey George Baker says he will not race again after suffering severe head injuries in fall in February.
Baker, 35, suffered bleeding on the brain after falling from his horse on the frozen lake at St Moritz.
He rode over 1,300 winners in his 18-year career, and won the St Leger at Doncaster in 2016.
"Although I will not be able to race-ride again, I consider myself extremely fortunate to be where I am now," he said.
Baker, Flat racing's tallest jockey at 5ft 11ins, spent eight days in a trauma unit in Switzerland before returning to Britain, and was discharged from hospital in April.
Speaking to At The Races, Baker said he is making progress with his recovery and wants to stay within the racing industry.
"Getting my driving licence back is a big thing. It's frustrating having to depend on other people having to drive you around," he added.
"Now I have to concentrate and that's become easier as time goes on and hopefully it will keep on improving - but I'm well aware at some stage it is going to slow down.
"And if this is as good as it's going to get, I'll take it."
BBC horse racing correspondent Cornelius Lysaght
I suppose we probably knew this news was coming at some point, but it makes it no less of a shock.
For a career as successful as that of Baker - all achieved despite being the jockey-unfriendly height of 5ft 11ins - to finish in this way is desperately sad.
His long-renowned reputation as one of racing's nice guys is confirmed by his philosophical reaction to events, basically saying he was lucky to have pursued a career he loved for a long time, but must now move on.