It was an unusual constituency, because Middleton and Prestwich were physically separated by Heaton Park, a large green area bequeathed to Manchester City Council, and had nothing whatsoever in common.
Prestwich was a well established middle class suburb with a large Jewish minority, and during the inter-war years boasted several millionaires.
The new constituency of Heywood and Middleton in 1983 resolved this mismatch by linking together the two adjacent towns in the Rochdale borough, and was held by Labour right up to 2019.
The 2018 Boundary Commission Review, which aimed to reduce the number of MPs from 650 to 600, and was subsequently shelved, had proposed to restore the Prestwich and Middleton seat.
The political parties had been making preparations for an election to take place from 1939 and by the end of this year, the following candidates had been selected; However, the sitting MP, Nairne Sandeman, died on 23 April 1940, resulting in a by-election.