Terminal 1 was opened by Queen Elizabeth II in April 1969. It was opened by Elizabeth. Terminal 1 was the Heathrow base for British Airways' (BA) domestic and European network and several of its long-haul routes before Terminal 5. The acquisition of British Midland International (BMI) by BA owner International Airlines Group in 2012 meant that British Airways took over BMI's short-haul and medium-haul destinations from the terminal. Terminal 1 was the home base for most Star Alliance members, although some were also located in Terminal 3.
Terminal 1 closed at the end of June 2015, now being used to expand Terminal 2, which opened in June 2014. Several new gates used by Terminal 1 were built and are being retained as part of the Terminal 2 development. Along with British Airways, the last tenants were El Al, Icelandair (moved to Terminal 2 on 25 March 2015) and LATAM Brasil (the third to move to Terminal 3 on 27 May 2015). British Airways was the last operator at Terminal 1. Two flights of this carrier, one from Hanover and the other from Baku, marked the terminal closure on June 29, 2015. British Airways operations moved to Terminals 3 and 5.