The Economist notes that the wild card in the upcoming U.K. election "is a party that has barely sniffed power since the first world war: the Liberal Democrats. Although Labour strategists are reluctant to admit it, the third-party Lib Dems may threaten the government's chance of another big majority more than the Tories do."
In fact, Robert Waller, co-author of the Almanac of British Politics, argues that there is a "significant realignment of the traditional political spectrum in Britain" under way.
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