Peter Mandelson, European trade commissioner, has said the protectionist stances taken by the US presidential candidates risk taking the world trading system back by decades.

In an interview with the BBC’s Hardtalk programme to be broadcast on Thursday, Mr Mandelson said: “It is irresponsible to be pretending to people you can erect new protection, new tariff barriers around your economy in this 21st century global age and still succeed in sustaining peoples’ living standards and jobs. It is a mirage and they know it.”