Mojo Star – runner-up in two Classics and the Ascot Gold Cup for Richard Hannon – could be retired after he finished lame in the Dubai Duty Free Finest Surprise Stakes at Newbury on Saturday.

The five-year-old, who was second in Adayar’s Derby and occupied the same spot behind Hurricane Lane in the St Leger before finding only Kyprios too good in last year’s Gold Cup, was making his seasonal return after a 310-day lay-off.

The lightly-raced son of Sea The Stars was fourth to surprise winner Grand Alliance in the Group Three contest registered as the John Porter.

However, Kevin Stott’s mount, owned by Kia Joorabchian’s Amo Racing, hung in the closing stages and was taken to a nearby veterinary hospital in a horse ambulance.

Hannon said: “He came in lame and has gone straight to the vets in Newbury to Jamie O’Gorman.

“He has a bit of a history, so that’s why he doesn’t run too often.

“That’s all we know at the moment – he was lame and it doesn’t look great. But he is a horse who has been a big part of our lives for five years.

“He is a class horse. He is a gentleman and also a horse very close to his owner’s heart. He is in the best place and he’ll be fine.

“Whether he continues his racing career or not, is probably doubtful. He has given us several great days and has been a pleasure to have about.

“He’ll be OK. But he is so generous. He travelled great and then he started hanging and he thinks that’s when it happened. I would think it might be suspensory, but he has such a big heart the horse he’s run right to the line. That’s why we all love him.

“He is a very special horse.”