The Manchester Exchange by-election of 27 June 1973 was held after the death of William Griffiths on 14 April of the same year. The Labour Party won the by-election in what had traditionally been a safe seat. Due to an administrative oversight, the by-election was held on a Wednesday, rather than the Thursday which had been usual since the mid-1960s. Only one by-election since has been held on a day other than a Thursday, the Hamilton by-election, 1978.