The by-election was caused by the appointment of Thomas Williams, Labour Party Member of Parliament (MP) for Warrington, as a High Court Judge.

It had long been regarded as a safe seat for the party, and even in 1979, generally a year of poor results for Labour, Williams won with a majority of 32.8%.

[1] In mid-term government and behind in the polls, they did not expect to advance and stood Stanley Sorrell, a London-based bus driver, and unusually for a Conservative, an active trade unionist.

John Fleming stood on a platform opposing immigration and the Trident nuclear weapon system, while also calling for British troops to withdraw from Northern Ireland.

According to the next day's edition of The Glasgow Herald Roy Jenkins had "emerged as a triumphant loser", coming close to victory and taking votes from both the Conservatives and Labour.

However he said "But in losing, it is by far the greatest victory in which I have participated" going on to claim that the figures made it possible that an SDP-Liberal government would be returned at the next election with a large majority.