The philosopher Hannah Arendt described fascism as the “temporary alliance of the elite and the mob”. If so, it has only ever been beaten by a temporary alliance of the centre and the left. In How to Stop Fascism, Paul Mason calls or a new Popular Front – learning the lessons of France and Spain in the mid-1930s.

The Popular Fronts were not just electoral pacts between liberalism, socialism, progressive nationalism and communism. They were mass cultural movements, with grassroots bodies that operated independent of party hierarchy and discipline. And they were transformative cultural movements, taking over and energising everything from the movies to glossy magazines to dance music.

But they went further. All successful anti-fascist movements, and democracies in the 1930s enacted antifascist laws: banning uniformed parades, controlling weapons ownership, monitoring the flow of finance to far right groups and ultimately outlawing the fascist parties themselves.

Mason argues we need a nuanced form of this – a Militant Democracy 2.0 – focused both on maintiaing the rule of law, forcing the police and armed forces to obey and implement the law, and regulating social media to drive hate speech and incitement offline.

Finally, Masin argues, we need to revive the anti-fascist ethos. The far right is at war with concepts of “virtue” and “justice” – and the universal rights of all humans – so we need to defend them with vigour.

In a moving final chapter Mason describes his visit to the Majdanek death camp in Poland, warning: “500 people escaped from Majdanek. Nobody would escape a facility built for the same purpose today”.