Cameron must not let this crisis go to waste

Few European leaders have been luckier than David Cameron. First he was sent Ed Miliband. Now events in Greece may be about to present him with a solution to the thorniest problem of his second term: how to negotiate a new form of EU membership for Britain that the Tory party can rally behind come the referendum.

The Prime Minister’s critics delight in claiming that his European problem is of his own making. Two years ago, he promised a referendum on EU membership before the end of 2017. But he couldn’t have survived without making such a pledge. It was his way of stopping his party arguing about Europe; without it, he could not have gone into the election claiming that he led a united party. It was also a way of wooing back those Tory voters who had gone to Ukip — without Cameron in No. 10, they could be told, there would be no referendum.