By Daniel Dombey, US diplomatic correspondent

There was a flash in Hillary Clinton’s eyes just now as she talked about the issue that is occupying ever more of her time as Secretary of State – Iran’s nuclear programme.

Last month the US-led campaign to increase pressure on Tehran took her to Qatar and Saudi.  Arabia, where King Abdullah welcomed her with a lavish lunch and watched a few minutes of a football match as he sat beside her wearing a frayed pair of Nike trainers. (Later on he switched his giant television to off-road truck racing.)

Iran has also been a constant concern for Clinton during her present swing through Latin America and the position of Brazil, which is currently sitting on the UN Security Council, is particularly important. Read more