During the early years of the 1950s it was realised in Britain that very soon the nation would be facing hordes of high flying Soviet bombers carrying nuclear weapons. An interceptor was thus required, capable of climbing much faster than anything currently on the drawing board anywhere in the world. Inspired by the late-war Messerschmitt Me 163, Saunders-Roe conceived the SR.53 as a testbed for and predecessor to the SR.177 - which, they projected, would be capable of Mach 2.35 and, more importantly, a brake release to 70,000 ft (21,000 m) time of 3 minutes 51 seconds.
The SR.53 featured an Armstrong Siddeley Viper jet engine and de Havilland Spectre rocket, mounted one atop the other in the tail. It was itself a very capable aircraft which could achieve Mach 2.2, though it was never taken there. Ultimately the project fell apart in the late 1950s for a number of reasons. The clincher came when West Germany opted to purchase the F-104 from Lockheed, instead of the SR.177, which shocked many. It was later discovered that Lockheed had throughout the ‘50s, ‘60s and ‘70s established a practice of bribery which ultimately led to the Foreign Corrupt Practices Act signed into law by President Jimmy Carter. Regardless, the SR.53 did fly and one survives today at RAF Cosford.