UK security adviser ‘attended’ US-Iran talks and judged deal was within reach

Powell’s presence at the talks, and his personal close knowledge of how they were progressing, was confirmed by three sources. Photograph: Leon Neal/Getty Images

Britain’s national security adviser, Jonathan Powell, attended the final talks between the US and Iran and judged that the offer made by Tehran on its nuclear programme was significant enough to prevent a rush to war, the Guardian can reveal.

Powell thought progress had been made in Geneva in late February and that the deal proposed by Iran was “surprising”, according to sources.