In Kubrick’s film, a rogue American air force commander orders a nuclear strike on the Soviet Union – but he doesn’t know that the Russians have built a Doomsday Machine that will automatically explode and spread lethal radioactive contamination all over the world if American nuclear weapons land on the USSR. So everybody dies.

Moscow doesn’t want the United States to make the same mistake in real life, so it has just let us know that it is building a mini-doomsday machine. It is awkward to say this sort of thing through diplomatic channels – “I have the honour to inform Your Excellency that we can now destroy half of your country with only one explosion” – so the preferred method is to get the word out by an accidental “leak”. In this case, the leak occurred on November 10 in the Black Sea resort of Sochi, where President Vladimir Putin was meeting with his senior military officers.

A cameraman for state-owned Channel One television “accidentally” filmed a general studying a poster of a new weapon called “Status-6”, a giant torpedo (a “robotic mini-submarine”, the poster called it) that can travel up to 10,000 km at high speed carrying a huge payload – like, for example, a truly gigantic thermonuclear weapon. And the film clip was broadcast all over Russia before the “mistake” was discovered.

“It's true some secret data got into the shot. Therefore it was subsequently deleted,” said President Putin's spokesman, Dmitry Peskov. But the complete text and a cutaway diagram of the Status-6 are now available on a hundred websites, and the Kremlin doesn’t seem particularly upset. The explosive core of the warhead would be a massive thermonuclear bomb – perhaps as big as 100 megatonnes, almost twice as big as any bomb ever tested. Around this core would be wrapped a thick layer of cobalt-59, which on detonation would be transmuted into highly radioactive cobalt-60 with a half-life longer than five years.

This is crazy talk, but the Russians have always lived in fear that the United States might somehow develop the ability to destroy Russia without suffering serious retaliation. And the truth is that the American military have never stopped looking for some way to do exactly that. The latest US gambit is anti-ballistic missile (ABM) defences to be based in Eastern Europe, allegedly to defend against nuclear missiles coming from Iran. But Iran doesn’t have any nuclear weapons, and it may never get them. Yet the American ABM system is going to be deployed in Poland and Romania in the near future. Moscow is therefore convinced that the whole project is really intended to shoot down its own missiles shortly after launch.

There is no realistic possibility that the American ABM defences could really destroy all or even most of Russia’s missiles, but that is exactly what Putin is saying to his generals on the sound-track just before the TV clip focusses on System-6.

System-6 is not scheduled to be operational until 2019-20, and it may never be built at all. But the old game of nuclear one-upmanship goes on even though the two countries are no longer really enemies. It is pointless and potentially very dangerous, and President Obama might usefully spend the last of his political capital putting an end to it.