USSR SS20 nuclear missile
The former USSR almost launched a nuclear missile attack in Europe in 1983. "SS20 irbm" by ChrisO

A nuclear war between the former USSR and West that almost broke out in 1983, would have annihilated much of Europe, according to newly-released documents. The crisis came about when the Communist USSR mistakenly became convinced Nato exercises were real and moved nuclear missiles to their launches while assigning priority targets.

The Nato exercise - "Able Archer 83" - involved highly realistic wargames involving heads of state, radio silences, and culminating in a simulated nuclear attack. The wargames were so realistic the Soviets became convinced they were real and began planning a nuclear attack of their own. If the Soviets had launched their long-range missiles, the West would have retaliated and it is thought much of Western Europe would have been destroyed and hundreds of millions killed.

Relations between the USSR and the West were already at a low. Bellicose US President Ronald Reagan was embarking on a controversial "Star Wars" programme, the Soviet leadership was growing old and paranoid, and in September that year the Soviets shot down a civilian airliner, Korean Air Lines Flight 007, over the Sea of Japan with the loss of all 269 aboard.

Former US President Ronald Reagan angered the USSR by embarking on his Star Wars programme. Getty

Newly-released documents in the US, analysed by the New York Times, reveal that in November that year, the world came closest to nuclear armageddon since the Cuban Missile Crisis of 1962. A 1990 analysis of the incident by the President's Foreign Intelligence Advisory Board reported: "In 1983 we may have inadvertently placed our relations with the Soviet Union on a hair trigger."

The report said that the scale of the Warsaw Pact's military response to Able Archer "strongly suggests to us that Soviet military leaders may have been seriously concerned that the U.S. would use Able Archer 83 as a cover for launching a real attack." The report concludes: "Some Soviet forces were preparing to pre-empt or counterattack a NATO strike launched under cover of Able Archer."

The only other comparable crisis was the Norwegian rocket incident in 1995, when a high-range rocket launched from Norway was mistaken for a Trident missile and Russian President Boris Yeltsin had to decide whether to press the nuclear button. Now, as relations between Russia and the West deteriorate once again, far fewer armed nuclear missiles are possessed by each side - but there is still enough nuclear firepower in existence to destroy the world many times over.