“So, effectively what you are doing is using the computers in the network to block the network,” said Little slowly, but looking somewhat confused; as well he might, thought Walker.

“Exactly, Prime Minister,” replied Allenby crisply. “But the really clever thing about Rasputin is that we can activate it when we want to. Most worms go into action as soon as they enter the system. But Rasputin sits in their system, dormant, until we want it to create chaos.”

“OK . . . So how do you get into the network in the first place?”

“Good question, Prime Minister,” GCHQ Director Berry intervened. “Initially we tried to mount an operation with the CIA and MI6 to break into the servers of Russia’s National Defense Control Center, the NDCC, while it was being built. However, to give them credit—and the Russians are seriously good at this sort of thing—we failed. One reason is that their servers are Russian-made, which maximizes their resistance to our offensive cyber capabilities. That by the way, Prime Minister, is another conversation for another day, about our own foreign-built servers . . . but I digress . . . Anyway, any defense is only as good as its weakest links. And Nicola here found a way in.” He smiled like a magician producing a rabbit from a hat, before pointing back to Allenby and so inviting her to explain.

“You’ll appreciate, Prime Minister, that any computer connected to the internet is susceptible to infiltration and takeover. We had to find a way to access a closed network like the one used by the Russian General Staff. So we looked for an individual with access to the closed network into whose open-network computer we might be able to install a virus.”

“And . . . ?”

“PJHQ hosted a visit a few years ago from a group of Russians who were setting up the NDCC, before Crimea—when relations were still OK. Well, naturally, my predecessor took advantage of it and laid the ground work. The team monitored the computer usage of a number of the colonels when they were back in their hotel and managed to get IP addresses and other details. Roll the clock forward and one of those colonels is now a general in the NDCC, so we continued to monitor his usage and hacked into his computer with the details recorded from that time. We had clocked that he was a regular subscriber to a couple of dodgy websites and we also knew that he was in the habit of taking work home and transferring work from his laptop onto his office computer.