They have always been a source of material for comics, science fiction magazines, television puppet productions and Hollywood extravaganzas. Since the beginning of time men have seen strange objects in the sky, which there have been men of science and authority ready to refute and explain away... but never completely. There is always the 10 per cent of 'sightings' that cannot be explained. The Ministry of Defence investigates every UFO report made to them. Now they have allowed Man Alive to film what, they believe, may be an explanation. But the ufologists are not convinced. On film and in an outside broadcast from Banbury in Oxfordshire - the scene of nearly 1,000 UFO sightings since last August - the sceptics, the scientists and the saucer spotters come together.