Former Greek finance minister Yanis Varoufakis comes to the National Theatre for what will be the most cerebral event in the build-up to Christmas. Varoufakis, a divisive political figure, is certain to present challenging perspectives on recent political and economic events. The Philosophical Theatre programme is fascinating. In previous editions, it has attracted some of the world's leading intellectuals, from Vanessa Redgrave to the economist Thomas Piketty and radical thinker Slavoj Žižek, and it looks set to continue in the same vein. Opposite Varoufakis will be the evening's host, Srećko Horvat.