‘In a free state, tongues too should be free,” wrote Erasmus 501 years ago. In truth, although Britain was often more tolerant than many countries, people have never been entirely free to speak their minds here. Blasphemy and sedition got you into trouble for centuries. There was uproar when Ken Clarke invited Oswald Mosley to address the Cambridge Union in 1961. The law has always rightly forbidden incitement to violence.

But the Speaker John Bercow’s call to “no platform” President Trump was not based on any claim that he might incite violence, and nor are many of the bans on controversial speakers that are routine at universities today. They are about the giving and taking of offence. Julie Bindel, a radical feminist, was banned from