The world is facing its greatest refugee crisis since the Second World War, with sixty-five million people displaced worldwide by violence, of whom eleven million are from the cauldron of the Syrian civil war. Meanwhile the international system for dealing with refugees is broken, and the shock waves of the crisis have created deep fissures in Europe and the USA.

The causes are complex, but Alexander Betts and Paul Collier highlight three in particular: the end of the Cold War, which weakened many smaller states that had depended on aid from the two superpowers; the spreading of Wahhabi ideology internationally by Saudi Arabia; and the long-term crises affecting around fifty fragile states such as Afghanistan, Iraq and Somalia. Large numbers of migrants are fleeing poverty, not violence – a million Africans, mainly economic migrants, are at this moment estimated to be waiting in Libya in the hope of crossing to Europe once calmer sailing weather returns to the Mediterranean.

Betts is an expert on refugees while Collier is an economist who has advised several British prime ministers. Refuge is written from a centre-left perspective and offers a compassionate but clear-eyed analysis. Its authors are unafraid to confront various bien-pensant shibboleths.

They focus first on the 10 per cent of refugees