Segregation: a Global History of Divided Cities' Laurie Taylor talks to Carl Nightingale, the author of a groundbreaking new book about the ideology and practice of racial segregation in the city. Traversing continents and millennia, he analyses the urban divide from its imperial origins to postwar suburbanisation; from the racially split city of Calcutta to the American South in the age of Jim Crow. Finally, he considers the extent to which separation by race continues to deform the contemporary city. Also, the sociologist Malcolm Brynin, charts the causes and consequences of pay gaps between different ethnic groups in the UK.Producer: Jayne Egerton.