Sunday’s Derrinstown Stud Derby Trial looks like becoming the most significant of all the pre-Epsom prep races, following news from Aidan O’Brien that he may run his three most fancied Derby contenders in the Leopardstown race. Japan, Broome and Anthony Van Dyck are all in the top five of the Derby betting at 12-1 or shorter and a clash between the trio could well determine the identity of the raceday favourite for the Epsom race next month.

O’Brien had intimated at the weekend that Japan would be aimed at the Chester Vase, which appears to be his preferred Derby trial, but the colt’s name was missing when final entries for Wednesday’s race were published. The trainer explained, during racing at The Curragh on Monday: “Japan and Anthony Van Dyck had an easy week about three weeks ago so we don’t want to go too far away, but we need to get a run into them and they will improve a lot from what they do.

“Japan is entered at Lingfield [on Saturday] but I’m half-thinking of running him in Leopardstown with Anthony Van Dyck and Broome.”

O’Brien had bad news for backers of Mount Everest, last seen running Japan to a short-head in the autumn. A 20-1 shot for the Derby, he has had a setback which will put him on the sidelines for a month, preventing him from going to Epsom.

Norway is the new 7-2 favourite for the Chester Vase, in which O’Brien also runs Gentile Bellini and Sir Dragonet. “He’s the main one, that Ryan [Moore] rides,” the trainer said, and Norway’s Derby odds tumbled from 33-1 to 20-1 with most firms on the strength of that endorsement.

But the Ballydoyle man has others to run in key trials this week, naming Mohawk and Circus Maximus for the Dee Stakes on Thursday and Western Australia for the Lingfield Derby Trial at the weekend. While he may have a runner in next week’s Dante Stakes, he has said the York race is a bit too close to Derby day for his purposes.

In a surprise, O’Brien indicated a potential change of plan for Sunday’s 1,000 Guineas winner. “I initially thought about the Oaks for Hermosa but it’s possible that she could come back here for the Irish 1,000 Guineas,” he said.

As there is only a week between the two Classics, it seems most unlikely that she could take in both. O’Brien already has the Oaks favourite in Pink Dogwood but Hermosa is only a point or two bigger with most firms at around 6-1.