The day Huntspill Head blew its top was a day the locals would remember for a long time to come. The town was five miles from the power station, but the Shockwave rippled through like an earthquake. People fell over in the streets and in their houses. According to official records, four hundred and twelve claims were received for new window panes, as buildings contorted slightly and glass dropped out. The tremor lasted no more than ten seconds, and then it was over. It happened three hours and ten minutes after I had left.

Almost everyone in the town looked westwards, towards the nuclear power station which they had fought so hard to stop being built, convinced that finally their fears had come true. They saw first a small plume of smoke rise; it rose for several seconds and then curved over westwards; then the containment building of reactor number three ceased to exist. It turned into a brown, grey and blue cloud, billowing out for several minutes in all directions, and then the billowing stopped and nothing more came out of the blackened crater in the ground.

The cloud rose, and spread out, until it was vaguely the shape of a fat cigar; it was four miles wide and fifteen miles long, and expanding quite quickly. It moved swiftly, blown by the fifteen-mile-an-hour wind westwards, straight down the Bristol Channel and out towards the Atlantic Ocean.

Only four people died as a result of the explosion and the subsequent lethal cloud; shipping in the Channel and out in the Atlantic was warned of the cloud’s size and direction, and was able to steer clear – all shipping, that was, except for an expensive cabin cruiser which had broken down in the mouth of the Channel. The cabin cruiser had sailed only a few hours before from a tiny marina near Huntspill, and was bound for Kinsale. On board the cabin cruiser were the skipper and three technicians from Huntspill Head; one was an electrical inspector, one a computer programmer and one a hydraulics engineer. There were three empty seats on the boat: these should have been filled by Patrick Cleary, Horace Whalley and Ben Tsenong. The centre of the cloud travelled straight across the boat, and although the four men went below, the polished teak decking offered them little protection. By the time the cloud had passed by, neither the men nor the boat were very nice to look at. Within half an hour, the last of the four men had died.

I had flown from Huntspill Head straight back to Strategic Headquarters in Shropshire; the reactor was still intact, and the southwesterly was blowing strongly.