Aidan O'Brien expects jockey Ryan Moore to leave it late before deciding on his ride in the Investec Derby at Epsom on Saturday.

The Ballydoyle handler has saddled five previous winners of the premier Classic and has seven horses in contention for this year renewal.

The shortest priced of the septet is Dee Stakes winner Cliffs Of Moher, who is disputing favouritism with a number of bookmakers.

O'Brien can also call upon Chester Vase one-two-three Venice Beach, Wings Of Eagles and the Anvil, as well as the first and third from the Derrinstown Stud Derby Trial, Douglas Macarthur and Capri.

Completing the trainer's team is outsider Finn McCool.

O'Brien said: "We've seven left in and they all seem to be well at the moment.

"The three from the Chester Vase are very strong possibles and the horse that won the Dee Stakes and the two from Leopardstown.

"Ryan doesn't have to make up his mind until Thursday morning. We'll go through all the horses and everything will be discussed. I wouldn't say anything is written in stone yet.

"The two horses from Leopardstown, Douglas Macarthur and Capri, ran a very good race in the Derrinstown and that's a very good trial.

"The three horses that ran in the Chester Vase all ran great races, we thought, and we were very happy with the horse in Dee Stakes."

With O'Brien's seven amongst 20 possible runners, tactics could prove key, but O'Brien plans to leave riding plans to his jockeys.

"The lads will sort that out themselves," he said.

"Epsom is a tough track, there's a lot of twists and turns and ups and downs and it is the Derby."

Mark Johnston believes likely favourite Cracksman will have to improve "significantly" if he is to confirm previous form with his Derby contender Permian.

The John Gosden-trained Cracksman got the better of Permian by a short head in Epsom's Derby Trial last month, but has not been seen in competitive action since.

Permian, meanwhile, has raised his game to win a Listed prize at Newmarket and the Dante Stakes at York and Johnston is quietly confident his charge can turn the tables on Cracksman.

"Cracksman is our best guide. Obviously and quite understandably his connections are going to expect him to come on from that Epsom race," said the Middleham-based trainer.

"We pulled a bit of a fast one on him there. He was on the inside and Permian held him in for a few strides and got first run on him. Cracksman managed to get out, came after us and caught us by a nose.

"There's nothing in it. They would have expected Cracksman to improve on that and beat us further, but this is the same track and a different distance and I think we're the more assured of the pair to benefit from the step up in trip.

"I don't think there's any doubt in anybody's mind that Permian has come on considerably since that Epsom encounter and Cracksman is going to have to improve significantly to beat him this time."

Johnston is pleased with how Permian has bounced back from his Dante triumph less than a fortnight ago and is encouraged that jockey William Buick has chosen to ride him.

He told At The Races: "Everything is looking good. We've had a couple of days of quite heavy rain, we desperately needed that, and hopefully it's going to brighten up now and we'll have a good preparation for the last few days.

"He's owned by Sheikh Hamdan bin Mohammed, Sheikh Mohammed's son. We consider Sheikh Hamdan's horses to be subsidiary of the Godolphin team and William Buick is the retained jockey.

"In some ways, with them having four horses in the race, it's quite flattering that Permian is the choice of William Buick. To my mind, that makes him the number one.

"Franny (Norton) won the Dante on him, but William has won on the horse before and he has had a number of different jockeys."