During the Sixties, the world arguably came the closest to all-out nuclear war as the US and Soviet Union tussled over ultimate supremacy both on the ground and in space. These tensions reached their peak in 1962 during the Cuban Missile Crisis, after Soviet Premier Nikita Khrushchev agreed to fulfil Fidel Castro’s request to place nuclear missiles in Cuba. Following the incident, both the US and the USSR continued to develop their nuclear weapons, becoming locked in a dangerous arms race, to create the ultimate weapon of mass destruction.
While reports of developing a 100 megaton bomb are widely known, papers seen by Express.co.uk show the two superpowers also probed the idea of creating something 10 times more deadly.
Letters from Solomun “Solly” Zuckerman, the MOD science advisor to former Prime Minister – Harold MacMillan – expose the shocking realities.
Dated September 1962, it reads: “In his Presidential Address to the British Association on August 29, Sir John Cockcroft [British physicist] referred to the fact that there are nuclear weapons which could destroy practically everything within a radius of 20 to 30 miles below the point of burst.
“Dr [Jerome] Wiesner had already told me that he had alerted President Kennedy to the possibility that even more destructive weapons than the kind to which Sir John was referring to would be technically possible by the end of 1965.
“He was, in fact, referring to the possibility of constructing 1000 megaton bombs, built essentially on the same principles which already make 100 megaton bombs a reality.
“In view of the immense strategic significance of these new developments, I took the opportunity when in the United States last week to discuss the matter both with Dr Wisner and Dr Harold Brown, Director of Defence Research and Engineering in the Department of Defence.”
Mr Zuckerman revealed in his letter how Mr Brown detailed the capabilities of a 100 megaton bomb.
He added: “The latter provided me with the opportunity of studying two detailed reports which had been prepared for the Department of Defence, by a team of external consultants appointed for the purpose.
“Their investigations dealt with the explosion of multi-megaton bombs at about 40 to 50 miles above the surface of the Earth and with the explosion of megaton bombs in varying depths of waters.
“The destructive effects of bombs exploded outside the atmosphere are due entirely to the generation of a terrific heat pulse consequent on the original radiation from a multi-megaton device.
“The estimated results suggest that a 100 megaton bomb exploded in average clear weather at a height of about 30 to 40 miles would, on a conservative estimate, be sufficient to ignite all combustible materials up to a radius of 55 miles.”
The letter then, more chillingly, exposed the capabilities of a bomb 10 times more deadly.
It continues: “The corresponding radius of effect for a 1000 megaton bomb would be 100 miles, that is to say, an area of about 30,000 square miles would be affected and in clear weather would have an even more devastating effect.
“The study also showed that, if the Russians were to use this method of attack in average clear weather on the US and detonate one 1000 megaton bomb, a large part of the US would be on fire.
“A corresponding attack on the USSR would have the same effect, although, from the charts I studied, it would appear that the US would be the more vulnerable of the two.”
The Cold War tensions would last for more than 40 years until a change in Soviet mindset under Mikhail Gorbachev culminated in the fall of the Berlin Wall.
However, the eighth and last leader revealed in 2006 his real thoughts on what caused the fall of communism in Eastern Europe.
He said: “The nuclear meltdown at Chernobyl, even more than my launch of Perestroika, was perhaps the real cause of the collapse of the Soviet Union five years later.”
The Chernobyl disaster was a devastating nuclear accident that occurred at the Chernobyl Nuclear Power Plant near the city of Pripyat, Ukraine, on April 25, 1986.
It is considered the worst nuclear disaster in history and is one of only two nuclear energy disasters rated at seven – the maximum severity – on the International Nuclear Event Scale, the other being the 2011 Fukushima Daiichi nuclear disaster in Japan.
Initially, after the Chernobyl disaster, Mr Gorbachev and the Communist Party downplayed the incident both domestically and on the world stage, calling it a minor event that “requires no special measures to protect the population”.
Moscow’s handling of the disaster went on to expose the reality of human error within the Soviet system and introduced doubt and questions of competence directed at the Kremlin not seen since before World War 2.
Mr Gorbachev was unable to recover and as questions mounted so did the pressure, until eventually the regime collapsed and the Berlin Wall coming down will forever be seen as the moment symbolising the Soviet Union’s demise.
However, these comments suggest that Chernobyl was the real turning point in Soviet history and the disaster arguably made the wall coming down an inevitability.