The BAC TSR-2 was a remarkable airplane that never made it into production. Its primary mission was low level strike, similar to that of the F-111. It had a high wing loading of 147 lb/sq.ft, requiring blown flaps. It was powered by a pair of Bristol Siddeley Olympus 22R (Mk 320) engines rated at 22,000 lb dry (the Mk 593 engines went on to power Concorde). In April 1965 the Government cancelled the project, with an intention to buy the F-111, because it would be cheaper. Cost escalation of the F-111 eventually made it more expensive than the now-cancelled TSR-2, and the government settled for a combination of F-4s (which were unsuitable for low level strike) and Blackburn Buccaneers to fulfill the tactical strike role.