The Eastleigh by-election shows that the British electoral system is becoming increasingly perverse.
The Liberal Democrats retained their seat in the Eastleigh by-election on 28 February 2013 because their diminishing electoral base still received tactical votes from the Left and because the protest and xenophobic rightwing vote (i.e. UKIP) was still slightly less.
The result was:
Liberal Democrat 13,342 32.06% (-14.44%)
UKIP 11,571 27.80% (+24.00%)
Conservative 10,559 25.37% (-13.93%)
Labour 4,088 9.82% (+0.22%)
Interestingly, had AV been in operation, as the Lib Dems wanted, then the Liberals would have picked up most of the transferred Labour vote, and UKIP most of the much higher Tory vote, handing the seat to UKIP.
I know this is a by-election, but the general point should still be made. Britain now has a complex multi-party system and the single seat constituencies, with no proportional top-ups, increasingly leads to perverse results.