At the time of the Cuban Missile Crisis, Britain was America's first-line defence, a vulnerable, but unsinkable 'aircraft carrier' on which the United States based the Strategic Air Command's first-strike elements of their America's nuclear deterrent. The Strategic Air Command's UK bases and the RAF's V-Force were ordered to the highest state of readiness at any time during the Cold War. Nuclear weapons were loaded, some nuclear-armed aircraft went on round-the-clock airborne patrol, others were held at cockpit readiness. But the British public was largely unaware that, as tensions rose thousands of miles away, the UK itself was under imminent threat of armageddon.

The book focuses on the implications for Britain of the covert deployment by the Soviet Union of ballistic nuclear missiles ninety miles off the US coast. It follows the crisis as it developed in London, Washington and Moscow. It looks at secret planning in the UK for World War III, and the activities of the JIGSAW Group (Joint Inter-Services Group for the Study of All-Out War). It also examines how close the UK went to activating 'Visitation', the code name for the movement of parts of the British State into a secret bunker referred to in Whitehall as 'The Quarry'.

Britain on the Brink also reveals the major strategic re-think the Cuban Crisis forced on Prime Minister Macmillan and the British Government.