In an interview with the Financial Times, John Kerry, the top Democrat on foreign policy in the US Senate, labels the long standing demand that Iran stop enriching uranium as ”ridiculous”.

A series of UN Security Council resolutions has demanded that Tehran halt enrichment, which can produce both nuclear fuel and weapons grade material. But Mr Kerry, a former Democratic presidential nominee who gave Barack Obama one of his first big political breaks, argues that the world’s big powers should frame more enforceable demands based on treaty obligations Iran has not met.