The famous shock at the climax of part three, when one of the "dead" Martians appears to lurch at its discoverers from the just-opened forward section of the capsule, was not in fact planned by director Rudolph Cartier but was the result of a lucky accident when the Martian prop slipped down from its position unexpectedly, resulting in giving the creature the semblance of movement and causing the actors - and audiences at home - to draw back in fright.
Both André Morell (Professor Bernard Quatermass) and Richard Shaw (Sladden) were asked to reprise their roles in the film adaptation Quatermass and the Pit (1967). However, Morell was not interested in repeating himself while Shaw was unable to do so because of a prior engagement.
Noel Howlett (Vicar Gilpin) was the only actor to reprise his role in the film adaptation Quatermass and the Pit (1967).
Noel Howlett played Vicar Gilpin in the television series but played a different part (Abbey librarian) in the film version.
Michael Ripper (Sergeant) previously played Ernie in Quatermass 2 (1957), the Hammer film adaptation of Quatermass II (1955).
The original filmed inserts were edited into a two part compilation for a repeat broadcast in 1960 and still exist today.