Edward Stourton chairs a live discussion series in which guests set out their strong views on a subject, before being challenged by a panel of experts. Economist and writer Philippe Legrain argues that Britain should abolish all immigration controls. The movement of people across our borders should, he says, be as free as the movement of goods and services. Legrain's views are challenged by Sir Andrew Green, chairman of Migrationwatch UK, Labour MP for Keighley and Ilkeley Ann Cryer and Tony Saint, a writer and former immigration officer.