The British Aircraft Corporation TSR-2 (for “tactical strike and reconnaissance 2”) was a cancelled Cold War strike and reconnaissance aircraft developed by the British Aircraft Corporation (BAC) for the Royal Air Force (RAF) in the late 1950s and early 1960s. The TSR-2 was designed to penetrate a well-defended forward battle area at low altitudes and very high speeds, and then attack high-value targets in the rear with nuclear or conventional weapons. Another intended combat role was to provide high-altitude, high-speed stand-off, side-looking radar and photographic imagery and signals intelligence, aerial reconnaissance. Only one airframe flew and test flights and weight-rise during design indicated that the aircraft would be unable to meet its original stringent design specifications. The design specifications were reduced as the result of flight testing.
Source: BAC TSR-2 on Wikipedia