Nigel Kneale's script really captures post-war pioneering science, cold war fear and cosmic horror but grounds it all with large doses of humanity. Reginald Tate is perfect as the scientific evangelist, Professor Bernard Quatermass and there's some great studio-based set design. The programme is pretty tense in a knob-twiddling, oscilloscope-wobbling kind of way and contains an almost Lovecraftian fear of the unknown.
Unfortunately, only the first two episodes survive and it's extremely unlikely that any recordings will ever be found of the missing four episodes.
Jolly good fun, chaps!