The library shelves groan with histories of twentieth-century Britain. Most are humdrum. Indeed, one can count on the fingers of one hand those that are both scholarly and stimulating. To this select few, we must now add David Marquand’s Britain Since 1918, a work of verve and insight whose breadth of learning is only partially concealed by the grace of its style.

The central theme of twentieth-century politics in Britain is the working out of the implications of democracy upon a traditional and oligarchic regime. In 1918, the Representation of the People Act, commonly known as the Fourth Reform Act,