Few people would disagree with the proposition that the world has become a nastier place in recent years, or that it’s happened very fast, hastened by the growth of social media platforms such as Facebook and Twitter. It’s never been so easy to target total strangers, to shame them for a momentary lapse in judgement or to subject them to a barrage of poisonous abuse. A thoughtlessly worded tweet (this phrase would have meant nothing two decades ago) can destroy a career, while public figures struggle to differentiate between online bravado and seriously intended death threats.

Douglas Murray’s new book, The Madness of Crowds, describes this behaviour as ‘increasingly irrational, feverish, herd-like and simply unpleasant’. I don’t disagree with any of that and it’s essential that public figures take a stand against it. Sadly, we live in an era when some of them don’t, choosing to keep quiet out of fear of being targeted by an online mob, or actively encouraging intemperate abuse of opponents as a political strategy. In the USA, the spectacle of a president who behaves like a teenage Twitter troll has gone from being a shocking aberration to a daily occurrence.

Perhaps surprisingly, given his place in the front rank of those engaging in a reckless coarsening of public discourse, Donald Trump makes only one appearance in Murray’s book. It comes in a section where Murray discusses the opprobrium heaped on the rapper Kanye West after he first praised