The head of the British Army tonight unleashed a stark warning that Russia could open hostilities "sooner than we expect", Mirror.co.uk reports.
General Sir Nick Carter insisted he was not suggesting Russia "wants to go to war in the traditional definition of the term.".
But the Chief of the General Staff said Britain "may not have a choice about conflict with Russia", declaring bluntly: "You may not be interested in war, but war is interested in you."
Sir Nick also warned British troops and equipment could stay in Germany to confront the rising threat, paving the way for a screeching U-turn as the UK continues to pull back forces home following the end of the Cold War.
It came as Sir Nick gave a major speech warning defence cuts will leave Britain exposed to threats from Russian cyber attacks.
He said at the Royal United Services Institute in London: "I’m not in any way going to suggest that Russia wants to go to war in the traditional definition of the term.
"But there are factors that bear on the question of intent. And one needs to understand Russian psyche, their culture, and their philosophy of pre-emption.
"Russia, I think, could initiate hostilities sooner than we expect - and a lot earlier than we would in similar circumstances.
"Most likely they will use nefarious sub-Nato Article 5 Treaty actions to erode the capability of Nato and threaten the very structure that provides our own defence and security.
"This is the divide and rule which the international order is designed to prevent.
"I don’t think it will start with little green men - it will start with something we don’t expect. We should not take what we've seen so far as a template for the future."
In the landmark speech he stressed the importance of a “forward mounting base” to give NATO troops a head-start in tackling potential invaders.