Midnight Lace

Although its theatrical origins (Janet Green's Matilda Shouted Fire) aren't exactly disguised, this is a smoothly efficient variation on the 'frightened lady' thriller. Just married to English businessman Harrison, Day's the American in London progressively unravelling after threatening anonymous phonecalls and voices in the fog. Perhaps surprisingly for an actress who always seemed to keep plenty in reserve, her hysteria's pretty full-on, and the taut screenplay keeps up the pressure with a string of worthy suspects (wheedling McDowall, scheming Marshall, disturbed war vet Gavin). Suavely effective, with extra fun spotting the joins between the authentic location work featuring Dotty's stand-in, and the star herself back in Burbank on the least convincing London street this side of The Spy Who Shagged Me.