In September last year, David Cameron told the UN general assembly: "As people in north Africa and the Middle East stand up and give voice to their hopes for more open and democratic societies, we have an opportunity – and I would say a responsibility – to help them." The Arab Spring uprisings had provided a chink of light for those living under repressive regimes, and it was now up to western democracies to help them throw open the door to a bright new future.
Yet over the past six months,…