But because Conservatives fear that they would not win an outright majority in a proportional representation (PR) system, the Lib Dems could secure only a more modest prize: a referendum on keeping FPTP or adopting the alternative vote (AV).

ECONOMIST: Constitutional reform in Britain

Because, under Germany's system of proportional representation, the Greens got 47 parliamentary seats, but under France's majority-voting system its Greens, the main environmental party, got a mere half-dozen.

ECONOMIST: France

Sri Lanka's system of proportional representation makes the magical two-thirds majority hard to reach.

ECONOMIST: Another romping success for the Tiger-slayer