Aidan O'Brien admitted nerves were jangling throughout the vast Ballydoyle operation as he prepares Camelot for his date with destiny in Saturday's Ladbrokes St Leger at Doncaster.

A rare opportunity was offered to the media to see the unbeaten colt completing a light piece of exercise on Monday morning, and he strode up a three-furlong stretch of woodchip gallops under Kaname Tsuge, the Japanese work-rider entrusted with such previous titans as Galileo.

O'Brien seemed happy to safely tick off another small test before the crucial examination, when Camelot attempts to become the first horse since Nijinsky in 1970 to complete the English Triple Crown of Guineas, Derby and Leger.

"The tension is just about bearable at the moment, I'm sorry," he said apologetically as Camelot appeared from the Tipperary stable complex, kept at a safe distance from errant cameras and spectators.

"He's breezing today, he'll do a half-speed tomorrow and then breeze for the rest of the week."

The son of Montjeu was given a serious racecourse trial at Leopardstown around a month ago but has not competed in public since the Irish Derby at the end of June, where he was far less impressive at a saturated Curragh than he had been at Epsom.

O'Brien said: "The ground would hopefully stay good - that's what went wrong at the Curragh - he hasn't got a soft ground action. He's very low, he doesn't move off the ground.

"But all we want is Kaname to say he's OK."

The other question mark over a horse described as "like no other" by a trainer who has seen a plethora of exceptional animals flow through his care, is a first try at an extended mile and six furlongs.

"The distance is different - it's nearly two miles and there's no doubt about it, they nearly have to be a Gold Cup horse to get that trip in our experience," O'Brien said.

"When they go beyond that mile and a half, that's when the real stamina must kick in."

"He's not a horse who fluctuated much in his weight but he's going to be a bit heavier than in any of his other races. When you're a three-year-old, your weight doesn't change much early on, but as they start to mature into a four-year-old later on, it can.

"Stayers don't build up as much as middle-distance horses, but he's not long or lean, he's round and strong. He's built like a miler."

While Camelot is long odds-on in the betting for the final Classic of the season, he is also 5-2 favourite with the sponsor for perhaps the most prestigious event of the European season, next month's Prix de l'Arc de Triomphe.

O'Brien must leave any forward plans are in the hands of the ownership power-trio of Derrick Smith, John Magnier and Michael Tabor, and said: "I don't know. We always had three, maybe four races in mind for this year, that was what I thought.

"The lads will make that decision. All those things are there and the decision will be made later on. All we've thought about is up to this. It's so far, so good, but there are another four days after today."

It does, however, seem assured Camelot will remain in training as a four-year-old.

While he would have managed an achievement not seen in 42 years on Town Moor, the feats of Frankel and Sea The Stars in recent seasons have raised the bar in terms of stud value.

"Before, it was make a stallion and get him off quick," O'Brien said.

"Now it's make a stallion and expose him - push him a bit. People want to see horses being tested, expose their weaknesses and their strengths."