CHELTENHAM, England, March 12 (Reuters) - Top ⁠Irish trainer Willie Mullins threatened on Thursday to stop bringing his ⁠best horses to the Cheltenham Festival after taking issue with the ‌quality of the ground.

The most successful trainer in the history of the event withdrew odds-on favourite and last year's winner Fact to File shortly before the day's Ryanair Chase feature race ​after finding the conditions too hard.