Hayes and Harlington is a constituency[n 1][n 2] in the west of London represented in the House of Commons of the UK Parliament since 1997 by John McDonnell of the Labour Party, who also served as the Shadow Chancellor of the Exchequer from 2015 to 2020 until his suspension and whip withdrawn on 23 July 2024, as a result of voting to scrap the two child benefit cap.

Its London Heathrow Airport component has most of the border with Buckinghamshire and Surrey and its shape is near-square with a north-east square attached: Hayes and Yeading.

The south-west is Heathrow Airport, which is the largest single provider of employment including its many associated businesses, such as retail, international distribution, cargo handling and parking throughout the seat and nearby.

Newer housing in the seat adjoins the Grand Union Canal and reduced pollution is expected from less diesel rolling stock on the main line.

[4] The constituency of Hayes and Harlington voted 58.25% leave versus 41.75% to remain;[5] this is in contrast to the public stance of incumbent MP, John McDonnell, at the time of the referendum.

2024–present: The London Borough of Hillingdon wards of Belmore, Charville, Hayes Town, Heathrow Villages, Pinkwell, West Drayton, Wood End, and Yeading.