This film, which also screens at BFI Southbank on Friday 13th Septmeber, is part of the Passport to Cinema season and tonight will be introduced by Dominic Powers. Details here.
Chicago Reader review:
This genuine SF classic (1956) says a good deal more about the McCarthyist hysteria of the early 50s than about the danger of invasion from outer space by soul-stealing “pods.” Don Siegel's superb little effort, with its matter-of-fact isolation of hero Kevin McCarthy (ironic, no?) from the smarmy complacency of a small town gone to hell—and way beyond—points the way to his gripping action films of the 60s and 70s (Madigan, Coogan's Bluff, Dirty Harry).
Here (and above) is the trailer.