Following the resignation of Labour MP Rosie Cooper on 30 November 2022, the seat was won by the party's candidate Ashley Dalton in the by-election held on 9 February 2023.

[3] West Lancashire is home to a significant proportion of those working at managerial and professional levels and an above average retired age quotient.

1997–2010: Aughton Park, Aughton Town Green, Bickerstaffe, Birch Green, Burscough, Derby, Digmoor, Downholland, Halsall, Knowsley, Lathom, Moorside, Newburgh, Parbold, Scarisbrick, Scott, Skelmersdale North, Skelmersdale South, Tanhouse, Upholland North, Upholland South, and Wrightington.

[10] In September 2022 Rosie Cooper announced she had accepted a new role as Chair of Mersey Care NHS Foundation Trust and would therefore resign as MP, triggering a by-election.

1: After nominations were closed, Sen was suspended from UKIP after sending an allegedly anti-semitic tweet to Liverpool Wavertree Labour candidate Luciana Berger.