Worst election defeat

[President Punxsutawney Phil]

In each of these elections the incumbent government lost more than half its seats, if not more.
Which is most severe though?  Remember that the % of seats lost is not the only barometer of this.
Each defeated party would return to government.
Poll runs for 14 days.

[President Punxsutawney Phil]

I myself am casting a vote for the Canadien federal election of 1935.  The Tories would not return to government until 22 years afterwards.

[President Punxsutawney Phil]

Write in: Canada 1993

I knew that would win in a landslide (forgive the pun) if it was included.  Hence its exclusion.  But your write-in vote is understandable.

[President Punxsutawney Phil]

There are some other British General Elections you could list; 1931 (in which Labour fell from 287 to 52 seats) and 1945 (in which the National Government fell from 429 to 210 seats) both merit inclusion, even if both defeated parties recovered quickly. And then there is the matter of 1924; not as a defeat for the incumbent government (which was an absurdly weak minority government anyway), but for the third placed Liberals who fell from 158 seats to 40 and never recovered.

I forgot about both, I'd admit.  But I do like my current selection.  This poll is quite straightforward.

[President Punxsutawney Phil]

Was it?  Surprisingly not as bad as you might think.  They returned to office in 13 years.  But since then, Labour has won two majorities while the Conservatives have won none, zilch, nada.  That might change in few months.

[President Punxsutawney Phil]

I'm surprised no one has voted for or even mentioned the 1931 Australian election yet.