It could only have happened at the height of cold war paranoia. To counter the threat of Soviet invasion, the UK planned to bury 10 huge nuclear landmines in Germany, declassified army documents from the 1950s reveal.

The extraordinary weapon was designed to cause mass destruction and radioactive contamination over a wide area to prevent an occupation by Soviet forces. Each mine was expected to produce an explosive yield of 10 kilotons, about half that of the atom bomb the US dropped on the Japanese city of Nagasaki in 1945.

The mines were to be left buried or submerged by the British Army of the Rhine. They would then have been detonated by wire from up to five kilometres away or by an eight-day clockwork timer. If disturbed or damaged, they were primed to explode within 10 seconds.

“It may look bizarre now, but this weapon was a product of its time,” says Lesley Wright, who is researching the history of the UK’s nuclear weapons programmes at Liverpool John Moores University. “It was a response to the perceived threat of overwhelming Soviet superiority in conventional weapons,” Wright says.


Blue Peacock

Nuclear historian David Hawkings revealed the plan for the nuclear mine, which was abandoned after four years of research and development in the 1950s. Hawkings retired two years ago from the Atomic Weapons Establishment (AWE) at Aldermaston in Berkshire and his account, based on records released by the government, appears in the latest edition of Discovery, the AWE’s science and technology journal.

Development work on the mine, which was codenamed Blue Peacock, began at the Armament Research and Development Establishment at Fort Halstead in Kent in 1954. The weapon was designed, its components tested (short of fission) and two prototypes constructed, as part of a secret army “atomic demolition munitions” programme.

Blue Peacock was to consist of a plutonium core surrounded by a sphere of high explosives, all encased in steel. The design was based on Blue Danube, a free-fall nuclear bomb weighing several tonnes that was already in service with the Royal Air Force. But Blue Peacock, weighing over seven tonnes, would have been much more cumbersome.

Fibreglass pillows

The steel casing was so large that it had to be tested outdoors in a flooded gravel pit near Sevenoaks in Kent. If questions were asked, Hawkings says the army’s cover story was that it was a container for “an atomic power unit for troops in the field”. In July 1957, army leaders decided to order 10 Blue Peacock mines and to station them in Germany.

Hawkings describes their plans for deploying the weapons in the event of an imminent Soviet invasion as “somewhat theatrical”. One problem was that the mines might not work in winter if they became too cold, so the army proposed wrapping them in fibreglass pillows.

In the end, the risk from radioactive fallout would have been “unacceptable”, says Hawkings, and hiding nuclear weapons in an allied country was deemed “politically flawed”. As a result, the Ministry of Defence cancelled Blue Peacock in February 1958.