Brennan's blunder was copied by the claimer Xavier Aizpuru on Come On In leaving Stone Island, the only other runner left standing, to complete the course and win under amateur rider Rupert Wakley.
Brennan eventually brought Holkham Bay home to take third place, but not until he had returned to, and dismounted in, the unsaddling enclosure where Len Wordingham, the gelding's trainer, vociferously ordered him to remount get back out on to the track and complete the course.
Meanwhile, Aizpuru had also completed, bringing Come On In home for second place.
Brennan was suspended for 14 days. The ban runs from 26-31 May inclusive and 5-7, 11, 13-14, 18 and 21 June.
Brennan said: "I misjudged it and that's it."Reuse content