Upminster was a constituency of the House of Commons in east London, which returned one Member of Parliament (MP) to the House of Commons of the Parliament of the United Kingdom, elected by the first-past-the-post voting system.

1974–1983: The London Borough of Havering wards of Cranham, Emerson Park, Gooshays, Harold Wood, Heaton, Hilldene, and Upminster.

1983–1997: The London Borough of Havering wards of Ardleigh Green, Cranham East, Cranham West, Emerson Park, Gooshays, Harold Wood, Heaton, Hilldene, and Upminster.

1997–2010: The London Borough of Havering wards of Cranham East, Cranham West, Emerson Park, Gooshays, Harold Wood, Heaton, Hilldene, and Upminster.

This usually safe Conservative seat was won by Labour in the landslide of 1997.