During the Second World War the electoral register was not kept up to date despite significant population movements, especially in the London area (which contains all three constituencies listed below). Consequently, only those eligible to vote in the constituency at the outbreak of war were eligible to vote in the by-elections and many voters were physically unable to as they were located elsewhere; in addition the major parties did not compete against each other. The lowest turnout in peacetime since 1918 was 18.2% at the 2012 Manchester Central by-election. The lowest turnouts since 1918 have been: