Labour Party had won in 1945 and Clement Attlee came in as the PM to replace Winston Churchill's Conservative (ironic name from an Indian perspective) Party.

Not sure of what side of the significance of these elections you seek, but "Inglorious Empire" by Shashi Tharoor and "Empire:How Britain made the modern world" by Niall Ferguson can offer contradicting ideas of the rise and the demise of the British Empire which was triggered soon after the 1945 elections.