Cooper had served as MP since the 2005 general election. She announced her resignation in September 2022.[6] In November, The Times reported that Cooper was delaying her resignation in an attempt to secure a peerage, meaning that the writ of election could not be moved until January 2023 at the earliest.[7] Cooper resigned her seat on 30 November, by means of being appointed as Steward of the Chiltern Hundreds.[8] The by-election was the first scheduled in 2023 and was the first by-election held in the West Lancashire constituency.
Candidates
Andy Burnham, the Mayor of Greater Manchester, declined to run for Labour amid speculation that he may want to enter Parliament again in the future,[9] and football broadcaster Gary Neville also declined to stand for the Labour Party's nomination.[10]
In October 2022, Ashley Dalton, a candidate for Rochford and Southend East in 2017 and 2019, was confirmed as Labour's candidate for the by-election.[11] Labour had shortlisted three women to be their candidate: Dalton; Emma Fox, former shortlisted candidate for Warrington South and daughter of Speaker of the House of CommonsLindsay Hoyle; and Louise Harbour, former deputy leader of Knowsley Council until she lost her seat in the 2022 local elections.[11] Other candidates on the longlist had included councillor for Knowsley ward Adam Yates; county councillor for Skelmersdale West Julie Gibson; Michael Denoual; and Nikki Hennessy.[12]
The Conservative Party confirmed in October 2022 that Mike Prendergast, an Ormskirk-based solicitor and councillor for Dukes ward on Sefton Council, would be their candidate in the by-election.[13]
The Liberal Democrats announced that Jo Barton, former councillor for Meols ward (also on Sefton Council) and candidate for the same constituency in the 2017 general election, would be their candidate.[14]