I believe our borders should be open. But if that is not politically acceptable for now, Europe should at least open up a legal route for people from developing countries to come work here. Over time, hopefully, we can move to a position where borders are completely open. Persuading skeptics won’t be easy. That’s why I think the argument for free migration has to be made at several levels: a principled case: it increases freedom and reduces injustice; a humanitarian case: it helps people much poorer than ourselves; an economic case: it makes us richer; and a pragmatic case: it is inevitable, so it is in everyone’s interests to make the best of it. Freedom of movement is not just a matter of human rights and international solidarity; it is in our self-interest. Opening our borders may seem unrealistic. But so too, once, did abolishing slavery or giving women the vote. Campaigning for people’s right to move freely is a noble cause for our time.