The divisions ripping the Middle East apart today are not new. Indeed, they are almost as old as the beginnings of Islam, 1,400 years ago.

But now they are also fuelled by oil and gas wealth, nationalism, ethnic rivalries and tensions over relations with the West – and, above all, attitudes to Israel. The mosaic of allegiances is complex, dynamic and at first impenetrable, with both unlikely alliances and feuds of exceptional bitterness.