David Cameron joined Barack Obama, Angela Merkel and Xi Jinping and other world leaders to play a “nukes on the loose” war game to see how they would cope with a terrorist nuclear attack.
The German chancellor grumbled at being asked to play games and take tests with the Prime Minister, US and Chinese presidents around a table with dozens of heads of state at a nuclear summit in The Hague.
Her complaints were overruled because Mr Obama was keen on the idea and in on the surprise.
In the war game, played out by actors in a series of short films, a terrorist attack with an atomic “dirty bomb” takes place in the financial heart of an unnamed but Western metropolis. “It could be the City of London, or Wall Street, Milan or anywhere”, summit leaders were told.
As the scenario unfolded, it emerged that the terrorists are from an unidentified global terror network and they have stolen nuclear material from an unidentified country that had poorly secured its radiological and nuclear stockpiles.
The bomb is being built in a clandestine laboratory with stolen uranium. It is an improvised explosive device but deadly and the clock is ticking, the leaders were told. Hundreds of thousands of people could be about to die.
“They had to give an answer on their own, in real time. It was like a test. It put them on the spot. Should they inform the public or keep them in the dark,” said a diplomatic source.
“Should they work with other countries or stand alone to try to thwart or minimise the attack? How should they make the cold calculation of how to get a more sustainable human cost in terms of deaths?”
Each world leader had a computer tablet with a touch screen options to make one of four responses to a series of four scenario films played by actors and mimicking the famous 1983 Cold War Hollywood thriller “War Games”, where a computer hacker triggers a nuclear missile scare.
In a competitive environment, with a ticking clock, the leaders had to make rapid choices before the results were presented to the group, anonymously stripped of their identities and followed by discussion.
Perhaps predictably at a world summit on nuclear security, the war game found that shared, collective international decisions were able to stop the terrorist network before they could actually build the dirty bomb.
US officials said that the unconventional approach had been designed to give a “scare you to death” shock to make leaders seriously think about the security of nuclear materials.
But not everyone was happy about playing the war game with the grumbling led by Mrs Merkel who was unimpressed with role-playing at such a high-powered gathering. Mr Obama, who helped plan the game, overrode the moaning. He had Elizabeth Sherwood-Randall, his lead national security adviser on the issue, helpfully by his side.
“Leaders had their doubts about participation on their own without their expert civil servants. It was about discussion and problem solving without leaders relying on written statements to read out. At the end the leaders were more enthusiastic,” said a spokesman for the summit.