In her “Pick of the Week” column on radio for The Daily Telegraph at the weekend, Charlotte Runcie recommended The Documentary: Where Are You Going? (tomorrow on the World Service at 7.30pm), for which Catherine Carr travels to the Mexican city of Tijuana, just south of where Donald Trump is promising to build a wall. Runcie says it “reveals compelling stories of transition, identity and politics by, simply, stopping people and asking them where they are going.”

The programme, recorded in November following Trump’s election victory, turns out to be part of a series — all available on the BBC iPlayer — in which Carr has asked the same question of people in Amsterdam, Kolkata (Calcutta), New York and “The Jungle” refugee camp in Calais.