Julian Glover had to perform his own stunts, including the scene where Colonel Breen falls over into the pit.
Andrew Keir celebrated his 41st birthday on set on April 3rd 1967.
Richard Shaw, who played Sladden in the TV version, was asked to reprise the role but could not because of a prior engagement.
Duncan Lamont, here playing the tormented drill operator Sladden, played the doomed astronaut Victor Carroon in the very first Quatermass TV series, The Quatermass Experiment.
Noel Howlett played the role of the vicar in the original BBC TV serial.
Van Heflin was considered for the role of Quatermass.
Anthony Quayle seemed to be cast before Kier stepped into the title role.
Despite not personally connecting with director Roy Ward Baker, Andrew Keir felt that the crew gelled together extremely well as a unit. This can partly be attributed to the fact that - prevented from lensing as planned at a full-up Elstree - the production team enjoyed the luxury of having the entire run of the empty MGM studios.
Early UK posters featured an illustration of John Neville as Quatermass, suggesting that he was a one time candidate for the role.
Edwin Richfield, who plays the Minister, played the role of Peterson in Hammer's earlier film Quatermass II: Enemy from Space a decade before.
If you look closely at the London Underground station walls, you can see quite a few posters from other Hammer projects such as The Reptile, Dracula: Prince of Darkness and The Witches, as well as My Fair Lady and Hotel. An old, partially-ripped poster for Sex and the Single Girl can be seen on the wall opposite the entrance to Hobbs End station.
Of the three Hammer Horror "Quatermass" films, this is the only one which "Quatermass" creator Nigel Kneale personally liked. This was largely to the fact that he was much happier with Andrew Keir's performance as the title character than he had been with Brian Donlevy's in The Quatermass Xperiment and Quatermass II: Enemy from Space. He described Donlevy as "a former Hollywood heavy gone to seed" and claimed that he was drunk during much of the shooting of the latter film, a claim which its director Val Guest repudiated.
Roney's mental image, seen on a small screen when the apparatus is being calibrated, is a shot from early in Four Sided Triangle, an earlier Hammer science fiction film.
The outside broadcast television cameras (and the TV channel glimpsed on a pub monitor) bear the genuine logo of ITV regional broadcaster ABCTV - ironic for an adaption of a serial made by the rival BBC channel.
The producers requested both orchestral and electronic cues from composer Tristram Cary in order to have a choice of scores to use. He provided around thirty minutes of symphonic music plus electronic pieces (to represent the Martian threat), though much of it was lost during post-production editing and recutting, occasionally being replaced with stock tracks.
Three decades on, Andrew Keir reprised the rôle of the Professor in "The Quatermass Memoirs", a five-part docudrama scripted by Nigel Kneale and transmitted on BBC Radio 3 in March 1996.
When Dr. Roney is picking at the eyeball of the dead Martian creature in his laboratory the pupils of the compound eye are a rectangular slot shape rather then round like a human eye. This is reminiscent of a goat's eye, a creature that has for centuries been associated with witchcraft and sorcery.