We eventually came out of that dive at about 13,000 ft. It was pretty close and as the characteristics were so different to the English Vampire at high mach numbers it seemed to me it must have something to do with those wretched Elephants Ears on the upper surface of the fuselage.
We redesigned the intakes and placed them on the bottom of the fuselage. I took the aircraft to beyond 40,000 ft an put it into a dive of about 75 degrees. This time instead of ducking its nose down, to my relief once I reached Mach 0.8 the nose began to rise. This was in 1951.
Apologies for using my own quote but could someone explain why the Vampire "Elephant Ears" being now placed beneath the fuselage instead of on top, would cause the aircraft to pitch up quite strongly at critical mach without any apparent action on the part of the pilot? It was never explained to us at the time. Mind you, memories fade somewhat after sixty years..