I believe that this is the inimitable Bristol Type-188 high-speed research aircraft, ca. 1962. Three prototypes were manufactured by the British firm to investigate the environment a follow-on Mach 3+ bomber was expected to encounter. Unfortunately (at least for us aviation aficionados), all of these projects were deemed too expensive - at least for British taxpayers. However, IMHO, the Bristol 188 did, in many ways, facilitate the subsequent production of Kelly Johnson's equally inimitable Lockheed SR-71 - but I digress.
