“This lecture is forbidden by radical opinion,” shouts one protestor into a hijacked microphone, as the mob fills the lecture theatre. “Forbidden! Forbidden!” answers the crowd, determined to prevent the Jewish geneticist Professor Mangel from delivering a talk titled “Do Rats Have ‘Families’?” It could have happened last week — but this scene is taken from the climax of Malcolm Bradbury’s satirical campus novel The History Man, published 50 years ago this year.