Following the longest public inquiry ever undertaken in the UK, 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. Funded by British Airport Authority, construction of the extension as part of the T5 construction took 6 years. As part of the construction, Heathrow Terminal 4 tube station was closed for 20 months between January 2005 and September 2006 to allow the connecting junctions to be constructed. The station opened on 27 March 2008 coinciding with that of Heathrow Terminal 5. It was designed by architects HOK in conjunction with Rogers Stirk Harbour + Partners. Although situated underground, parts of the station's roofing are made of translucentETFElaminate panels, allowing natural daylight to flood down both ends of all six platforms. It is the only station at Heathrow Airport where both the Heathrow Express and Piccadilly line services share the same station.
Services
Terminal 5 station is served by the following rail services:
Piccadilly line from platforms 1 and 2: half the trains on the Heathrow branch terminate here, via Hatton Cross and Heathrow Terminals 2 & 3. The other half do not serve Heathrow Terminal 5, running instead via the loop to service Heathrow Terminal 4 and Heathrow Terminals 2 & 3, before returning eastbound.
Heathrow Express terminus to and from Paddington station from platforms 3 and 4.
Free intra-terminal transfers
Until 2012, free transfer was not possible between terminals via the Underground, unlike on the Heathrow Express. In January 2012, free travel was introduced for Oyster card and contactless payment card holders between the Heathrow stations on the Piccadilly line. Journeys from Heathrow Terminal 5 to Terminal 4 via the Piccadilly line require a change at Hatton Cross; this journey is free, despite Hatton Cross not being part of the free travel zone.
Future links
From 2020, Heathrow Terminal 5 will be served by the Elizabeth line, as part of the Crossrail project. Network Rail has put forward a proposal for a Western Rail Approach to Heathrow, a short spur of track in tunnel which would run from a junction east of to Terminal 5 station. This would permit Great Western Main Line trains to run directly from and into Heathrow, without the need to change at Paddington. The proposal is currently at consultation stage and remains unconfirmed. In addition to the above rail links, Terminal 5 station also has two safeguarded "heavy rail" platforms for use by a west-facing connection to the National Rail network. The south-leaning proposal would spur off the Waterloo to Reading Line west of Staines railway station. It proposes direct rail services to London Waterloo, Reading, Woking, Guildford and Gatwick Airport. Due to the cost of replacing three level crossings, one in a very urban part of Egham, the proposals are currently unfunded.
