British intelligence warned its government that the US was ready to wage a "preventive" atomic war on the Soviet Union in the early 1950s, whatever the objections of its NATO allies, documents unearthed at the public record office reveal.
The US military was convinced that "all-out war against the Soviet Union was not only inevitable but imminent", the director of naval intelligence, Vice-Admiral Eric Longley-Cook, warned London.
The documents were discovered by Richard Aldridge, professor of politics at Nottingham University, England, whose book, The Hidden Hand, is published in the UK by John Murray next month.
The response in US military circles to the Soviet Union's success in exploding its first atom bomb in 1949 - four years before western intelligence predicted - reflected the kind of paranoia portrayed in the film Dr Strangelove.
Vice Admiral Longley-Cook, who along with other senior British military officers made regular visits to Washington, argued that the Soviet Union was too cautious to start a war.
However, he warned that American fascination with the ideas of preventive war was fuelled by McCarthyism and spread beyond the Pentagon, the US defence department.
"Many people in America have made up their minds that war with Russia is inevitable and there is a strong tendency in military circles to `fix' the zero date for war," he said.
"It is doubtful whether, in a year's time, the US will be able to control the Frankenstein monster which they are creating. There is a definite risk of the US becoming involved in a preventive war against Russia, however firmly their NATO allies object."
The Vice-Admiral described war-mongering fever in American cities whose inhabitants, he reported, "visualise in their own concentrated home town the ruins of Hamburg and Berlin". "These and other Americans say: `We have the bomb, let's use it now while the balance is in our favour. Since war with Russia is inevitable, let's get it over with now'," he said.
One US general was reported to have remarked that the West could not afford to wait: "We can afford, however, to create a wilderness in Russia without serious repercussion on western civilisation. We have a moral obligation to stop Russia's aggression by force, if necessary, rather than face the consequences of delay."
Another US general said the country was already at war with the Soviet Union. "Whether we call it a cold war or apply any other term we are not winning . . . the only way that we can be certain of winning is to take the offensive as soon as possible and hit Russia hard enough to at least prevent her from taking over Europe."
Winston Churchill, the then British prime minister, was initially sceptical of the Vice-Admiral's frightening observations, even suggesting he was a communist.