God I must have sat through Dr Fod a million times when it was foggy and flying was scrubbed at Coningsby mid 70's. That and the lox film with the guy on the ventilator at the end which was supposed to scare us into good practice when we still used to vent the lox pack onto the pan and freeze stuff in it for a lark.........'Oi what you lot doing'.....'It's just very thick radiation fog chief due to our location in a maritme temperate climate'.......'Er, right yeah I knew that'...............