Dougie Costello philosophical as he loses ride on Quiet Reflection

Former jump jockey Costello partnered the filly to two Group One wins last season and has expressed hiis disappointment.

"I just met Karl on the way out of Ayr racecourse there and I shook his hand and said, 'Thank you for giving me the chance,'" Costello told the Guardian.

"There's been no falling out. I want to be as positive as possible. This is racing and you get jocked off horses left, right and centre. I'm very grateful to Karl. My first year as a full-time Flat jockey, he gave me a great leg-up and I ended with four Group wins.

"My view is that to be a top-10 jockey you need a base behind you. It's just back to the grind now and see what we can find.

"I have always worked hard but I'll work twice as hard now and see if I can't get another Quiet Reflection or another Monet's Garden, another Wayward Prince or a Midnight Chase. I've been blessed all the way through my career with these good horses."

Burke had told Racing UK presenter Gordon Brown: "Martin Harley will ride her this year, we've had a chat with the owners and decided to have a change of jockey, he's agreed to make himself available."

The trainer also revealed he was left slightly disappointed with his filly after last year's Commonwealth Cup winner worked at Newcastle on Monday morning.

"She's in good form and looks fantastic," he said. "She actually worked at Newcastle today. I've seen her work better and her work has been a little workmanlike this winter.

"Whether she is just a year older and knows the gallops - I expected her to work a bit better this morning but I'm 90 per cent happy with her.

"There's only a handful of races she can run in. A Group Two as a prep for Ascot, hopefully the July Cup if the ground is right then depending which route we take maybe the Nunthorpe then Haydock and Champions Day."