At the height of the referendum campaign on Britain and the Common Market, one of the Labour Cabinet ministers who was leading the Keep Britain Out group, confessed to a private gathering that he was fighting with his hands tied behind his back.

‘The real reason to stay out is that we simply cannot compete’, he said. ‘Our productivity is too low, our machinery too old. We’ll be an industrial wasteland within a decade.’ ‘But we can’t base our campaign on that’, he went on. ‘We’d get hammered for being anti-British, for being doom merchants. We know it’s the truth but we just can’t say it.’

And now the same process is at work in what passes for a national debate on Britain’s new nuclear weapon. A vital part of the argument, which is commonplace among nuclear strategists, is being carefully kept from the public. It is about our part in nuclear blackmail. It is about the fact that, in the last analysis, the target of Britain’s nuclear deterrent is not Moscow, but Washington.

The simple and gruesome logic behind this follows from that classic scenario, a Warsaw Pact invasion of Western Europe. NATO can delay, but not stop the Russian tank armies from reaching the Channel. At such a point, the NATO alliance faces its dramatic test. An American President must then decide