This was a safe Conservative seat from 1983 to 1997 then became a Labour marginal for the remainder of its existence.
Boundaries
1983–2010
1983–1997: The District of Selby, and the District of Ryedale ward of Osbaldwick and Heworth.
1997–2010: The District of Selby.
The constituency covered the district of Selby and the south-eastern suburbs of the city of York (namely the parishes of Fulford, Heslington and Osbaldwick and Heworth Without[3]). It included the University of York and the Drax and Eggborough power stations.
2007 Boundary Review
Following its review of parliamentary representation in York and North Yorkshire in the 2000s, the Boundary Commission for England created a new seat of Selby and Ainsty. The new seat consists of much of the former Selby constituency, minus the south-western suburbs of York which are included in the (also newly created) seat of York Outer, plus rural areas south and east of Harrogate formerly part of the Vale of York constituency.
2024–present: The City of Leeds ward of: Kippax & Methley; and the District of Selby wards of: Barlby Village; Brayton; Byram & Brotherton; Camblesforth & Carlton; Cawood & Wistow; Derwent; Eggborough; Escrick; Hambleton; Monk Fryston; Riccall; Selby East; Selby West; Sherburn in Elmet; South Milford; Thorpe Willoughby; and Whitley.[5]