As part of Wednesday's Q.E.D. documentary, A Guide to Armageddon, two London couples each volunteered to carry out a ten-day 'consumer test' - underground in a nuclear shelter. Joy and Erik sealed themselves in a £10,000 buried steel bunker, six feet underground. Ken and Liz followed Home Office recommendations and dug their own 36-inch-wide emergency trench in the back garden. They, too, stayed down for ten days. This programme is a record of how the two couples coped underground during last winter's severe cold spell with only a fixed camera to observe them, completely out of touch with the outside world.