Quoit was silent for a moment. He appeared to be having a problem. He looked up, turning his head from side to side in short, violent jerks. At first I thought he was having a seizure or a heart attack. ‘Hrr,’ he said, ‘whrreer.’ He stood up, holding his hand to his mouth, and took several paces around the room, with his head tilted first to one side and then the other. With the hand that was free, he pointed at his mouth with repeated stabbing movements. Fifeshire followed him around the room with his eyes, a thick frown on his forehead. Quoit bent himself almost double, shook his head wildly three or four times, then stood upright once more holding his spectacles out in front of his face. ‘I’m sorry,’ he said, ‘I’m afraid I got my glasses stuck in between my teeth.’

I caught Fifeshire’s eye. Fifeshire looked worried – not about atomic devices, but about Quoit.

‘It would be possible to blow up power stations using nuclear explosives, certainly, and it would be very effective. If the objective of these people is to create widespread radiation fall-out, vapourizing the core by means of a nuclear explosive would be the best way. You see, the higher the explosion lifts the debris, the greater the distance down-wind over which it would spread. Conventional explosives would lift the debris a few hundred feet at the most; a nuclear explosive that succeeded in vapourizing the core could make a plume fifty to sixty thousand feet high – and that would travel a very long way downwind.

‘I think there are two ways these people could achieve their aims. The first would be to organize an internal sabotage of the power stations. One person in the control room of each power station, with the assistance of key accomplices, could achieve this quite simply. There would be no need for any explosives to be brought in. By creating malfunctions and taking the wrong corrective action, a lethal situation could be created in any reactor.’

‘I thought the systems were meant to be foolproof?’ said Fifeshire.