Britain’s ability to pre-empt or respond to threats risks being eroded if the UK does not keep up with its enemies, the head of the British Army will warn.
General Sir Nick Carter is also expected to highlight how Russia, in building an increasingly aggressive and expeditionary force, already boasts capabilities the UK would struggle to match.
During a speech at the the Royal United Services Institute he will point to Syria, where General Carter will say the Kremlin has repeatedly and publicly demonstrated its long-range strike capability.
And that Britain must also look closely at how countries are now being more creative in the ways in which they exploit the seams between peace and war.
“Our ability to pre-empt or respond to threats will be eroded if we don’t keep up with our adversaries,” the chief of the general staff is expected to say on Monday.
“State-based competition is now being employed in more novel and increasingly integrated ways and we must be ready to deal with them.
“The threats we face are not thousands of miles away but are now on Europe’s doorstep – we have seen how cyber warfare can be both waged on the battlefield and to disrupt normal people’s lives – we in – the UK are not immune from that.”
Mirroring Kremlin concerns made by others, General Carter will also highlight how last year Russia undertook simulated attacks across Northern Europe – from Kaliningrad to Lithuania.
Last month the chief of the defence staff Air Chief Marshal Sir Stuart Peach also addressed the threat of Russia, and said the UK’s military has prioritised the protection of undersea cables from the Kremlin, because if they are cut or disrupted there would be an immediate and “potentially catastrophic” hit to the economy.
And using her address at the Lord Mayor’s Banquet in London, Prime Minister Theresa May also said last year that Russia had “mounted a sustained campaign of cyber espionage and disruption” against other countries.
During his speech General Carter will stress that Britain “must take notice of what is going on around us” or that the ability by the UK to take action will be “massively constrained”.
“Speed of decision making, speed of deployment and modern capability are essential if we wish to provide realistic deterrence,” he will add.
“The time to address these threats is now – we cannot afford to sit back.”
General Carter’s comments come during a period of widespread speculation about possible cuts to personnel and equipment amid major pressure on the defence budget.
There have been calls to increase defence spending to 3% of GDP from some MPs, and reports there are plans to cut the armed forces’ strength by more than 14,000, as well as the combination of elite units of paratroopers and Royal Marines to save cash.
But, in the Commons during Defence Questions last week, Defence Secretary Gavin Williamson said “hard work” is taking place across Government to give the “right resources” to the armed forces.
Speculation about defence cuts has mounted in recent months since the launch of a review led by the Prime Minister’s national security adviser Mark Sedwill.
The review is examining all aspects of national security capabilities, fuelling concerns it will prioritise measures to counter cyber attacks and terrorism rather than major defence projects.
Last week in the Commons Mr Williamson would not comment on speculation that the defence element of the ongoing strategic defence and security review would be separated from it.