photo via John D Myers (click to view large) and reproduced here with John's permission who says;
"...My first airshow at Farnborough when I was 5 years old.....my Dad took the picture with a Voigtländer on Agfa slide film. Olympus engines designed for use in the TSR 2 were tested on this Vulcan XA 894. In July 1960, the airframe was modified to carry the engine, an Olympus 22R in a central nacelle. At Farnborough in September 1962, it did several low level passes with reheat on which were quite spectacular. BAC Warton's famous Chief Test Pilot, Wing Commander R P Beaumont, flew the aircraft on the 20th November. This turned out to be its last flight. On the 3rd December 1962, XA 894 was positioned on the detuner at Filton for a ground run and full power check but the aircraft was completely destroyed by a massive fire following an engine explosion. The crew all survived.."
Above; Roger Leitch photo
The explosion that destroyed XA 894 was the result of a low pressure turbine disc in the engine which failed during a full power ground test and punctured fuel tanks causing the fire. The explosion also destroyed a brand new fire engine in close proximity another part of the engine separated and stopped just short of hitting a prototype Bristol 188. The fire was so intense it was left to burn itself out..
a full account of the trials of XA 894 on the aviation archive org heritage site here