The UK Election's Many Swings

NO BRITISH election is complete without a swingometer. The classic version looks a bit like the bottom half of a clock, with the hour hand showing the “national swing” from one of the main parties to the other—and indicating how many seats will change hands as a result. It first appeared in the BBC’s report on the 1959 general election, as a hand-operated dial on a black-and-white map of Britain. These days it is snazzier, with digital animations. But in May it will be almost completely irrelevant. Though the fundamental mathematics of the election are unchanged—to win an outright majority, a party needs about 320 seats—the notion of a national swing has been thrown out. As a result, predicting the outcome of the election is even harder than usual.