Undignified is the adjective that best describes the graduands' supper. It may be the case that the gate-crashers to this function accounted for the grossly rude behaviour exhibited there. but more likely the graduands themselves should be held responsible for it.

The behaviour objected to: the continual interruption of speakers by a group of louts from the floor. Incidentally they were well hidden from view at the back of the Little Theatre, thanks to the inadequate seating arrangements. Their remarks were followed by loud clapping, and the kicking and rolling of empty beer bottles about the floor.