Ante-post favourite Riders Onthe Storm will miss Saturday’s Caspian Caviar Gold Cup after being declared a non-runner in error.

Formerly trained in Ireland by Gold Cup-winning handler Tom Taaffe, the six-year-old made a successful debut for Nigel Twiston-Davies in a valuable event at Aintree last month.

Despite a 13lb hike in the weights, the Scorpion gelding was the clear market leader to follow up at Cheltenham, but Weatherbys confirmed him a non-runner just after 9am on Friday morning, with an infection put forward as the reason for the withdrawal.

However, Twiston-Davies later confirmed that he had been mistakenly declared a non-runner, and while the yard attempted to contact the relevant authorities to rectify the error, he could not be reinstated.

Asked what had caused the mistake, the Naunton handler said: “It’s too complicated to go into, but it happened and that’s it.

“We tried to put him back in within 30 seconds, but rules are rules and we couldn’t.

“It’s desperately disappointing, but there you are.

“He’ll probably go to to Ascot next week now for a graduation chase.”

Several bookmakers announced they would void all bets on Riders Onthe Storm including Paddy Power, Unibet and Coral.