Quinn the tonic for Sonic Boy

Jimmy Quinn's successful partnership with Sonic Boy has ensured that he, rather than Pat Eddery, will be aboard the colt when he contests the Diomed Stakes at Epsom on Friday.

The Newmarket-based lightweight was replaced by Eddery when the colt finished third to the Derby hope Tamure in the Glasgow Stakes at York last month. But Quinn was back on board when Sonic Boy made all for a six-length victory in a handicap at Haydock a week later and Fulke Johnson Houghton, the colt's trainer, said yesterday: "Jimmy will ride him. He gets on well with the horse - he has won twice on him and done nothing wrong.

"He is stepping up in class but we don't have much option. I suppose Young Ern is the danger but I think Sonic Boy will run very well. He is in super form."

Simon Dow, trainer of Young Ern, said: "It is a slight deviation from our original plan which was to go straight to Royal Ascot for the Queen Anne Stakes, but I would say it is 60-40 he will run. He will handle Epsom, most horses trained here do."