The UK is living in “truly dangerous times” with the chance of “large-scale conflict” likelier than at any point in recent history, defence officials have warned.
At the same time, new weapons developed by rival states are growing in lethality.
China has a “world-leading” arsenal of hypersonic missiles that can travel at least five times faster than the speed of sound, making them very difficult to destroy once launched, officials said.
They signalled the best way to defeat such a weapon – like the DF-17 or longer-range DF-27 ballistic missiles – would be to locate the launch sites inside China and take them out before they are fired.
The comments were made as a group of journalists was given rare access to a top-secret military spy base in Cambridgeshire.
RAF Wyton hosts one of the biggest intelligence analysis centres among Western allies inside a complex called the Pathfinder Building.
Running 24 hours a day, seven days a week, analysts and other experts work inside a giant, grey, windowless room with a high ceiling, about the size of an indoor football pitch.
Teams are divided into sections, seated around white, curved desks, each with computers and screens, while television monitors beam in live images from satellite and drone feeds from areas of interest around the world.
One official said it is the “biggest top secret floor plate” dedicated to intelligence analysis, specifically for a group of close allies known as the Five Eyes – the UK, the US, Canada, Australia and New Zealand.
Red, glowing digits from a line of digital clocks along one wall give a nod to the allies and other areas of interest, offering the time zones for Washington, Zulu (GMT), Stuttgart, Moscow, Canberra and Wellington.
The hall is one of several classified sites across the country used by Defence Intelligence, which comprises around 4,500 personnel in total – two-thirds military, one-third civilian.
Staff are also deployed overseas on missions.
A second official said demand for the work of military spies is the highest they have known it since at least Russia’s first attempt to invade Ukraine in 2014.
“I believe we are living in truly dangerous times,” the official said, noting that the task for Defence Intelligence is to provide “insight and foresight”.
Underlining the importance of this kind of input, the official said: “There won’t be time from a warning to making significant changes to be prepared for large-scale conflict.”
The official added: “We are in a pre-war situation… [We are] at a point when large-scale conflict is more likely than it has been in recent history.”
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In addition, Grant Shapps, the defence secretary, has cautioned about a “pre-war world”, though without announcing any change of policy to better prepare the nation, including civilians and industry, for the reality of what a future war would mean.
A third defence official offered a view of the threat picture facing the UK and its allies.
“We are generally seeing a world that is complex and increasingly interconnected and has more threats of instability and competition,” the official said.
Russia – nuclear-armed and seeking to expand – remains the most acute threat facing the UK and its allies, but officials said they are “very alive” to the challenge posed by China.