Iran has been significantly expanding its covert nuclear weapons development since 2009, it has emerged. New intelligence uncovered by Iranian opposition group NCRI reveals that the regime’s Organisation of Defensive Innovation and Research (SPND) is running a secret programme to boost nuclear warhead capability, including mounting them on ballistic missiles able to strike targets over 1,900 miles away. The revelations come as Tehran prepares for a fourth round of proposed nuclear talks with the US in Muscat next week, with experts predicting they may derail negotiations.