Now the economists calculated, it's a back-of-the-envelope calculation, that removing all immigration controls would double the size of the world economy, and even a small relaxation of immigration controls would lead to disproportionally big gains. Now from an ethical point of view, it's hard to argue against a policy that will do so much to help people that are much poorer than ourselves. The famous Rand Study reckons that a typical immigrant who arrives in the US ends up with $20,000 a year, that's rough. It's not just the migrants themselves who gain; it's the countries they come from. Already, the migrants from poor countries working in rich countries send home around 200 billion dollars a year, through formal channels, and about twice as that through informal channels. And that compares to the neat a hundred million dollars that Western governments give in aid. These remittances are not wasted on weapons or siphoned off into Swiss bank accounts; they go straight into the pockets of local people. They pay for food, clean water and medicines, they help kids in school, they help start-up new business.