"Quatermass" met with a generally unenthusiastic critical response. Sean Day-Lewis wrote, "Although Piers Haggard's direction achieves much verisimilitude and the story is certainly enough to command some addiction; I did not feel exactly grabbed; the genre has moved some way since the 1950s and the Professor moves a little slowly for the 1970s". The reviewer in "The Daily Telegraph" found Professor Quatermass "far too unheroic and unresourceful to carry much interest" while "The Times" found the serial to be "a so-so affair". More positive was the "Daily Mail" who thought the serial was "not the best of Nigel Kneale but it equalled any of his earliest "Quatermass" stories". John Brosnan, writing in "Starburst" magazine, found the serial to be "a bitter reaction by a member of an older generation to the younger generation whose apparently irrational behaviour makes them appear to belong to a totally different species. Naturally in the traditions of sf, these failings are exaggerated to the nth degree. Thus muggers and juvenile delinquents become armed gangs and the hippy movement with its emphasis on mysticism, becomes the Planet Church. It's very much a story of Age versus Youth and significantly it's the older people who are impervious to the malign alien influence". This view is echoed by filmmaker John Carpenter who said, "Nigel was very embittered about the way of the world, as was shown, I think, in "The Quatermass Conclusion"".