Red and orange and yellow and blue

BRITAIN'S majoritarian, first-past-the-post electoral system means the country’s traditional third party, the Liberal Democrats, suffers most at general elections in terms of seats per vote won. Tactical voting against the Conservative Party has gifted the Lib Dems many additional votes, but few of those protest votes are translated into seats in the House of Commons. In 2010 over 5.5m of the Lib Dems’ 6.8m votes made no contribution to the 57 seats it won. The Tories and Labour are far less wasteful. Around two-thirds of their votes helped secure seats for both parties.

Another effect of tactical voting is that the Tories remain second behind the Lib Dems in 39 of the latter's seats. Moreover, in the 27 constituencies where the Lib Dems hold a majority of less than 10% the Conservatives are placed second in 19. Labour is often a distant third. In 2010 in the South West, a Lib Dem stronghold, for example, the nearest a Labour candidate got to the Lib Dem was 20 percentage points behind; in most other seats the gap was over 40. A similar pattern prevails nationally. Disaffected Lib Dem voters would have to traverse a sea of blue to guarantee Labour wins in most seats. These factors mean the wipeout of the Liberal Democrats may not be as catastrophic as national polls suggest.