Alwyn Turner writes early on that Little Englanders is ‘an attempt to take the temperature of the nation as it emerged from a century that had dominated the world and was beginning – whether it knew it or not – a long process of decline’. Perhaps for that reason, or perhaps because the high (and low) politics of the years from 1901 to 1914 – the Edwardian era continues for four years after the death of the eponymous sovereign, up to the lights going out all over Europe in August 1914 – have been so exhaustively covered in recent years,...