The difficulties of riding half a ton of thoroughbred round a course modelled on a Polo mint came out on the opening day of Chester's three-day May fixture yesterday as Housemaster won the Victor Chandler Chester Vase with authority, only for the stewards to take it off him.

The course's trial for the Epsom Derby was thus given to the Barry Hills-trained Peshtigo, who does not hold an entry at Epsom and who would scarcely have won this race if he had been required to pass the post just the once.

Richard Quinn was given a six-day ban for irresponsible riding "of a major nature" and his name was added to the list of top riders who will miss all or part of the York May fixture next week.

Quinn, whose suspension begins on the final day of York, May 13th, and runs uninterrupted for six days, was clearly making least effort of the Group Three's eight jockeys as Peshtigo came off the final turn in front.

Initially seeking the inside rail for Housemaster, trained by Michael Bell, the Scot had to snatch up and pull out inside the furlong pole as the leader's anticipated parting from the fence failed to materialise.

In doing so, he knocked Kieren Fallon's mount Lightning Arrow, who in turn rolled onto Frankie Dettori on Iscan.

Hardly had the horses pulled up before the klaxon signalling a stewards' inquiry sounded.

Just under 20 minutes later came the announcement that Peshtigo, beaten a length, had been promoted to first, with Lightning Arrow pushed up to second and Iscan to third, and Housemaster put behind his victims.

Senior stewards' secretary Patrick Hibbert-Foy explained their decision.

"The stewards had to answer five questions to determine whether it is of a major or minor nature regarding irresponsible riding," he said.

"On this particular occasion they considered that Richard Quinn placed in serious jeopardy the safety of Kieren Fallon on his right.

"They also considered that he substantially impeded him and they also considered that he created a gap when one did not properly exist.

"It should have been obvious to Richard Quinn that by pulling right, he was very likely to cause serious interference to Kieren Fallon, who was on his right.

"Therefore he has to be placed behind the horses with which he interfered.

"Frankie Dettori also had to hook up - he was involved in the incident - and thus Richard Quinn had to be placed fourth, behind the horses with which he interfered."

While accepting his punishment, Quinn stressed his move had been to save his own skin rather than sacrifice his opponents in winning the race.

"I came into the straight going well Michael Hills looked like he was going to roll off the fence," he said.

"I put myself in there to go up the rail, he then came in, so I have switched to go round him.

"I had my horse set alight and couldn't stop, and in doing that I have given Kieren a nudge.

"The horses were getting tired and it was over exaggerated, but the sad thing is that the best horse didn't keep the race.

"You have got to take it on the chin but I didn't do it as a manoeuvre to win the race - I did it for self-preservation, because I was angled to go up the rails and Michael has come in, and I was going to come down."

Bell, who will send Housemaster straight for the Derby, for which Ladbrokes offer him at 33 to 1, was sporting in his reaction to the result of the inquiry, saying: "It is tough on the horse because he won like a good horse. Let's hope we have better luck at Epsom."

Hills has the King Edward VII Stakes at Royal Ascot as Peshtigo's summer objective, but still holds a hope of Classic success for the bay in the St Leger.