Released in 1961, the film ups the ante on fears of nuclear apocalypse by imagining the Earth thrown out of its axis by simultaneous nuclear testing at both Poles. Britain swelters, then suffers thick fog, flash fires, cyclones and severe drought. The rest of the world suffers equally intemperate weather - but this is the best of what is to come. A government spokesman coolly informs the British public that the only thing that can save the planet from moving closer to the sun is (ironically) a chain of four nuclear explosions. The film closes as the countdown to the explosions ends.
Images of the impending global catastrophe are telegraphed through the confines of a Fleet Street press office and its newspaper headlines. There is no need for the tsunami/'quake/frozen landsape effects of later, bigger movies - the sight of typewriter rollers melting, a sudden heavy burst of dry ice on the Thames for the unexpected pea-souper, and a press hack being stricken by typhus, is enough to suggest the extremes of climate change.
The real power of the film comes from its pertinent subject matter (the leaders of the world enacting policies which serve the needs of the few, but which screw the rest of the world over) and from the script and performances.
Janet Munro and Edward Judd make a rather sympathetic couple, sniping then snogging in the best traditions of Howard Hawks. Their relationship is also pleasingly and respectfully adult (Look! A flash of bare breast! She's naked underneath that towel!) The film belongs, however, to Leo McKern as the older, savvier hack. It is he (of course) who begins to put two and two together, as the temperatures soar. It is he who lights a fire underneath Judd on the matter of his self-destructive impulses and his need to secure both girl and job. It is he who offers to walk out into the deserted streets of London to record the moments as the explosions go off.
It is also Leo McKern who has some of the best lines in the film, and the script itself is a witty, sharp and cynical confection. The British, it is suggested, would treat the extremes of climate change as a chance for some extra sunbathing, fighting, sex or boozing.
Not really science-fiction at all, then...