Trainer Sean Curran was left "flabbergasted" after his heavily backed runner Aces Full was prevented from running two minutes before he was due to take part in the novice handicap chase.
The stewards ordered the horse to be withdrawn following a request from the BHA’s integrity department to interview connections.
Aces Full had been off the track since being pulled up last October but attracted strong support during the morning, being cut from 14-1 to 9-4.
Curran said: “I am shocked and flabbergasted at what has happened and I don’t know why it’s been done. As far as I know I have not broken any rules. The horse is owned by my cousin Joe English but has been leased to me.
“He runs under my other name John Curran and I pay all the entry fees and jockey fees. It’s strange that there was no problem when he ran under my name last time and it makes me think the BHA has just taken action this time because the bookmakers have been concerned about the gamble.
“I have put a lot of work into this horse and all that time and money has been wasted now. I thought he would win today, although I was a little concerned by the horrible weather at Exeter.
“Joe would have backed the horse I'm sure, but he’s retired so I don’t believe he would have had a lot of money on. We are not a big stable and we need winners like this to make ends meet.”
At the request of the integrity department the stewards had asked the trainer to provide information regarding the selection of the race for the gelding, their expectations and the riding instructions.
Mark Scully, a spokesman for the BHA, said: “We are unable to provide any further details on this matter at the present time.”
I will look forward to seeing their reasoning. I dont see how you can stop a horse from running just because it has been heavily punted. If there has been some dubious laying on the exchanges to get it out in the first place then its a different matter.