Be My Royal, winner of the 2002 Hennessy Cognac Gold Cup, was disqualified at a hearing of the Jockey Club's disciplinary panel in London today.
Trainer Willie Mullins was in attendance at Portman Square to hear the fate of his charge, 14 months after the Irish gelding's shock victory in the Newbury showpiece. He was not fined.
Be My Royal failed a post-race drugs test for morphine, the source of which is thought to have been a contaminated food supply.
However, Mullins was ordered to pay legal costs of £5,000 after the two-day hearing.
John Maxse, the Jockey Club's director of public relations, said: "It is unusual for an application of this type to be made by the Jockey Club, but on top of the cost of having counsel represent us, the Jockey Club has had to take extensive legal advice and additional work. So the order was considered appropriate in this case."
The full findings will be made available next week and Mullins has seven days from that day to appeal.
Be My Royal's disqualification means that the Hennessy now goes to original second Gingembre, trained by Lavinia Taylor.
There was a glut of morphine positives around the time of Be My Royal's victory and the common denominator in most of them was a batch of feed supplied by Connolly's Red Mills.
The Newbury event is the highest-profile race involved. Between November 2002 and February 2003, 37 horses produced positive tests, of which 16 were winners.
So far, eight cases have been heard by the disciplinary panel. All the horses have been disqualified and fines for trainers waived after the panel was satisfied in each case that the source of the substance was a batch of Connolly's Red Mills 14 per cent Racehorse Cubes, which were being used in the relevant yards at the material time.