Although the raceday stewards found no breach, subsequent investigations by the British Horseracing Authority called into question a move by O'Donoghue aboard Red Rock Canyon.

The trio declined to comment after a disciplinary panel hearing in London yesterday while BHA public relations manager Paul Struthers said: "As all parties have seven days from the receipt of the panel's reasons to appeal, it would be inappropriate to comment on today's proceedings.

"However, I would like to stress that, in reaching their conclusions, the panel made clear that there was no attempt to cheat, simply that the breaches occurred due to ignorance of the details of the rule in question."

Dates for the riders' suspensions have yet to be announced and Murtagh and O'Donoghue will be free to ride in the Qatar Prix de l'Arc de Triomphe as no flat racing takes place in Britain that day.

Having elected to take an early lead in the Group One International, O'Donoghue manoeuvred his mount out to his left at the four-furlong marker, thus allowing Murtagh a clear passage aboard stablemate and 4-6 favourite Duke Of Marmalade.

O'Donoghue admitted he was guilty of a breach of Rule 153 (iv) which states, "A rider shall not make a manoeuvre in a race in the interest of another horse in common ownership...whether or not such a manoeuvre caused interference or caused his horse to fail to achieve the best possible placing".

The rule covering such a manoeuvre was amended in March 2007 following a similar inquiry six months previously where Ballydoyle were exonerated from any wrong-doing in the Queen Elizabeth II Stakes at Ascot.

O'Brien told the panel, chaired by Tim Charlton QC, that they were unaware of the change until all riders participating in this year's Ladbrokes St Leger were presented with a photocopy of the rule before that race.

Although not clear of the exact nature of the rule, trainer O'Brien passionately stressed to the panel that he was "paranoid" about the use of pacemakers following the QEII inquiry.