Following the longest public inquiry ever undertaken in the UK,[4] construction of the station was granted in November 2001 by transport minister Stephen Byers as part of the approval of the Heathrow Terminal 5 project.

[5][6] The proposed terminal site was not welcomed by London Underground, as it would be impossible for all three stations to be served from the same route.

[8] Heathrow Terminal 4 tube station was closed for 20 months between January 2005 and September 2006 to allow these connecting junctions to be constructed.

[13] Although situated underground, parts of the station's roofing are made of translucent ETFE laminate panels, allowing natural daylight to flood down both ends of all six platforms.

This would permit Great Western Main Line trains to run directly from Slough and Reading into Heathrow, without the need to change at Paddington.

It proposes direct rail services to London Waterloo, Reading, Woking, Guildford and Gatwick Airport.