Hayes and Harlington is a constituency 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. 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. Harlington is among the lowest-population components of the seat; with Hayes it gives its name to a railway station and with Hayes was the name of an urban district.