Kieran Shoemark says it is a “privilege not pressure” to team up with Gregory in Saturday’s Betfred St Leger at Doncaster.

Shoemark was called upon by John and Thady Gosden for the ride aboard Soul Sister in the Grand Prix de Paris earlier in the season and will again be aboard a horse usually piloted by Frankie Dettori, with the retiring Italian picking his Derby mount Arrest over the Queen’s Vase winner for his final ride in a British Classic.

It is arguably the biggest ride of Shoemark’s career as he steps out on Town Moor aboard one of the leading fancies for the final Classic of the season, but he is relishing the prospect of linking up with the Royal Ascot scorer, who has an obvious chance of handing him a first victory in one of racing’s crown jewel events.

Shoemark said: “I’m very happy with my mount in the race and wouldn’t swap him. As soon as Frankie made up his mind I found out.

“He’s a high-profile horse in a high-profile race. He’s one of the market leaders and to be riding a favourite in a British Classic is hugely exciting.”

When asked if the ride aboard Gregory would represent the biggest moment in his career, Shoemark added: “I’ve never ridden a favourite in a Classic, so you could potentially say that. I’ve certainly felt more pressure going into other races, but if I were to win the race it would be my biggest career win for sure.

“It’s where I want to be, so it’s a privilege not pressure and I look forward to it.”

Gregory will head into the race having suffered his first career defeat when third under a penalty in the Great Voltigeur at York, but Shoemark believes a return to further for the Wathnan Racing-owned colt will be in his favour.

He continued: “It was well documented the strong tempo throughout the race in the Great Voltigeur and all credit to Gregory for maintaining that and still finishing his race.

“He was only beaten four lengths and the other two that were taking him on the whole way finished tailed off. I thought it was a massive run and we know he will benefit for the step up in trip, so it is all systems go.”

Unsurprisingly, owners Juddmonte are delighted Dettori has sided with their colt.

Racing manager Barry Mahon said: “John called this morning to say that Frankie had thought about it, and with the rain he was happy to ride Arrest and I suppose when you sit down and go through the different variables, he knows Arrest handles that type of ground which is a big thing.

“I think it will be a hot race and in fairness, I don’t think it was an easy choice to make for Frankie and I’m not sure I would be able to make it.

“Ultimately I’m sure the rain is what swayed him and if you look back to this day last week, when I spoke to John we both said it looks like we won’t be running. The forecast was giving very little rain at the start of the week but the last I read they were up to 30 millimetres, so it’s been a rollercoaster of a week and the more rain that falls the better.

“We know he handles soft ground well and I’m not sure there is a whole lot more coming between now and Saturday, but if there is, then an odd shower won’t do it any harm.”

Alongside Gregory and Arrest, the Clarehaven stable also has a fine third string in the supplemented Middle Earth (Oisin Murphy), a hugely impressive winner of the Melrose at York’s Ebor meeting.

The King and Queen have a live chance of tasting success in a British Classic with the William Haggas-trained Desert Hero, himself a Royal Ascot winner, albeit in handicap company in the King George V Stakes.

He subsequently won the Gordon Stakes at Goodwood, narrowly beating Simon and Ed Crisford’s Chesspiece and the two will lock horns again.

Aidan O’Brien runs four in Great Voltigeur winner Continuous, Alexandroupolis, Denmark and Tower Of London meaning there were no withdrawals at the 48-hour stage.