“If we found out earth was doomed - say, by climatic changes - what would we do about it?”

Andrew Keir certainly cornered the market in shouty know-it-alls during the 60s and early 70s. You've got Father Shandor in Dracula - Prince Of Darkness (terrorises gormless villagers with his gun and enormous dress), Professor Fuchs in Blood From The Mummy's Tomb (no-one Fuchs with this Professor - not until he meets his match in his own daughter, anyway) and of course, the piece de resistance in enraged egotists, the fantastic Professor Quatermass.

A strange object is found buried under Greater London during the excavation of an Underground Tunnel. Enter Prof Quatermass and his assistant (tweedy Barbara Shelley).

Quatermass immediately susses out that the lump of blue plastic is a spaceship (clever lad, that Bernard), but no-one will listen to him - even when he realises that the ship's defence mechanisms have been causing strange things to happen in the area since the beginning of history.

Of course, all our 20th Century mucking about starts to have a big effect on the ship, and before you can say "oops", things have really taken a turn for the worse. (People running riot in a cannibalistic orgy, soldier's heads exploding - you know, the usual). 

This film's strengths lie in the slow build-up to the boffo climax - the noises the ship eminates and the effect it has on the more weak-willed of the people who come across it is terrifying, if you're in the right mood. Very little happens for quite a long time, but you're so intrigued that it doesn't matter.