Heathrow Runways
Heathrow was requisitioned from Faireys towards the end of WWII and equipped with 3 runways in the RAF triangle pattern (Nos 1, 2, 3)....it was always secretly intended to make it Londons civil airport postwar and around 1945 they began to build the 'Star of David' pattern of runways with Nos.4,5,6,7 making Runway 3 immediately redundant as it ran through the Central Area (see map).... there was an expansion plan made public to build 3 more runways in a triangle north of the A4 (Sipson area) but this was officially and publicly abandoned in the early 50s....by the early Sixties only No1 (then 28R/10L), No5 (28L/10R) and No2 (23L/05R) were still in use....05R stopped being used as T4 expanded and 23L was terminated around the Millenium.
The Sipson Runway appears to be inevitable....my personal view is that Gatwick and Stansted should also receive new parallel runways for air-safety reasons and regional planning reasons to take the pressure off Heathrow and the M25 and the Thames Valley roads