Heathrow Terminal 5 is a shared railway and London Underground station serving London Heathrow Airport Terminal 5. The station serves as a terminus for the Heathrow Express services to Paddington in central London, and for Piccadilly line services towards Cockfosters. The station is staffed entirely by Heathrow Express staff, unlike the other underground stations serving Terminal 4 and Terminals 2 & 3.The London Underground section of the station is situated in Travelcard Zone 6; it is the westernmost below-ground station on the London Underground network.HistoryThe station was opened on 27 March 2008. It was designed by architects HOK International in conjunction with Rogers, Stirk, Harbour & Partners. 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.