Top chaser Flagship Uberalles will not be returning to Noel Chance's Lambourn stables following a disagreement with the horse's American part-owner Michael Krysztofiak.
The seven-year-old had been switched to Chance from Paul Nicholls last year and won on his first outing for the Lambourn trainer at Cheltenham last November.
However a series of high-profile defeats most recently in the Grade One Ladbrokescasino.com Championship Chase at Sandown when the gelding finished only fourth behind Edredon Bleu seems to have prompted the fall out.
Chance said: "I asked Mr Krysztofiak not to bring the horse back here. He's actually in Newmarket being checked out at the moment for a breathing problem he may or may not have.
"Trainers like me dream of having Grade One horses like him in the yard so I'm obviously sad to see him go but things have not been good between myself and Mr Krysztofiak and that's the way it is.
"It seems he is fine when the horses are winning but it's very different when they are not. Things have broken down and I'm afraid that's about it."
Flagship Uberalles landed the Arkle Trophy at the 1999 Cheltenham Festival when trained by Nicholls.
It is not known who will be his next trainer, although Martin Pipe and Henrietta Knight are thought to be high on Krysztofiak's short list. - PA