Of all the baleful effects of the French Revolution, few have such a continuingly irritating presence as the categorisation of our politics into "Left" and "Right". As a growing number of people are discovering, and as Peter Hitchens points out in his new book, The Broken Compass (Continuum), the terms have almost no current meaning. There is no longer an ancien régime for the Left to assault or the Right to defend.

The more recent idea that the Right is full of free marketeers and the Left collectivists has been reduced to a barely discernible border dispute over the last decade under a Labour government. And if the Right was generally admiring of the military and the Left more pacifist inclined (so complete a misconception as to amount to an organised lie) then that idea was overturned by left-wing leaders from the 1990s, committing the military to many more engagements than their right-wing predecessors.

During the Cold War, there was some sense in defining a stance towards communism, ranging from hostility to acquiescence. But since its end, our political compass has not so much broken as become utterly outmoded. Using "Left" and "Right" to navigate our politics today is like dusting down your first book-size computer disc and trying to put it into your sparkling new laptop. It isn't just that it's not compatible - it no longer has a hole to fit in.