Britain is facing the most dangerous period since the Cold War, the head of the armed forces has warned – as a former Nato commander cautioned that failure to spend now would mean a “cost in blood”.
Chief of the Defence Staff Sir Richard Knighton told BBC Radio 4’s Today programme: “This is the most dangerous period that I have known.” He said Russia has been “probing, challenging, testing our defences”, and is “raising the stakes and risks crossing a line”.
“UK military chief Sir Richard Knighton warns of most dangerous period since Cold War as Russia probes defences.”
His remarks came as former Nato Supreme Allied Commander General Sir Richard Shirreff issued a chilling warning to the government, saying the country could suffer “catastrophic costs” unless ministers move immediately to shore up defences. “Spend now on defence or Britain will pay a cost in blood,” the Daily Mail reported him as saying.
Knighton said last year’s Strategic Defence Review was a “call to arms”, and while in recent decades the armed forces have focused on short, contained conflicts, the UK must now be ready for longer wars like the one in Ukraine. He highlighted how Russia has been “probing, challenging, testing our defences” closer to home: “We have seen in 2026 more long-range aviation from Russia. These are strategic aircraft that will go well into our own airspace. We’ve seen as many in 2026 as in 2025.” The airspace he referred to is the High North, which includes the Arctic circle and adjacent areas. The RAF intercepts Russian jets approaching UK airspace, though there is no recent case of Russian military aircraft actually entering UK airspace (12 nautical miles from the UK).
Knighton’s comments come ahead of the expected publication of the Defence Investment Plan, first due in autumn 2025 but repeatedly delayed. On Friday, the prime minister said the plan would be published before a Nato summit “in just a few weeks’ time”. Sir Keir Starmer said: “We’ve been working on that defence investment plan for some time, very closely with our armed forces, as you would expect, because we need that interaction.”
Asked whether the government is willing to give the military the extra funding it says it needs – amid recent criticism by former defence secretary Lord Robertson of the UK’s diminished capabilities – Knighton said he was confident ministers are aware of the threats and are increasing spending. “Exactly as the prime minister says, we need to spend more on defence and do it faster. The challenge for ministers is to make those difficult trade-off decisions,” he said.
The military chief also spoke about the changing nature of warfare, noting that drones and autonomous systems are going to become “increasingly important in the future of warfare”. He concluded: “I’m very clear that this is the most dangerous time I have known in my working life. And the risks and threats to this country are greater than I have known since the Cold War. And it is important that society and all of us recognise and understand that.”