Ancient Citizen said:
Which was promptly overturned by the conservatives at the following election.
Wrong....
The 1951 United Kingdom general election was held twenty months after the
1950 general election, which the Labour Party had won with a slim majority of just five seats. Labour called the election for 25 October 1951 hoping to increase their majority.
Labour defeat is significant for several reasons: the party polled almost a quarter of a million votes more than the Conservatives and their National Liberal allies combined, won the most votes that Labour had ever won (and has ever won as of 2014) and won the most votes of any political party in any election in British political history. Despite this, it was the Conservatives who formed the next government with a majority of 16.
Under the first past the post electoral system, Labour votes translated into increased majorities for MPs in safe seats, rather than into gaining new seats.