Sir Richard Knighton, the Chief of the Defence Staff, has declared that the UK faces its most dangerous period since the Cold War, as Russia “probes, challenges and tests our defences” and risks crossing a line. In an interview with BBC Radio 4’s Today programme, he said: “This is the most dangerous time I have known in my working life.”
His stark warning came as an influential cross-party group of MPs accused the government of damaging Britain’s safety by repeatedly delaying the Defence Investment Plan (DIP). The blueprint, first promised for autumn 2025, has been postponed several times and is now expected before a Nato summit in early July. Sir Geoffrey Clifton-Brown, chairman of the Public Accounts Committee, said the delay had emboldened the UK’s enemies and that ministers should “simply apologise”.
“Sir Richard Knighton says Russia probing defences, warns of longer wars, as MPs hit out over delayed defence investment plan.”
“Those responsible may argue there are good reasons for the Dip’s continuing absence, but our report makes clear that excuses … simply do not cut it,” he said. “Whatever the content of the Dip when it eventually does appear, the damage from its absence has been done – to the nation’s credibility, to its safety, to its armed forces, and to certainty within its entire defence industrial base.”
Lord Robertson, the former Labour defence secretary who authored the government’s Strategic Defence Review, has also accused Sir Keir Starmer of “corrosive complacency” and putting UK security “in peril”. In a speech in April, he attacked “non-military experts in the Treasury” for what he called “vandalism”.
Knighton warned that the UK must prepare for longer wars like the one in Ukraine, rather than the short, contained conflicts of recent decades. He pointed to increased Russian long-range aviation activity: “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.” He referred to the High North, which includes the Arctic circle, though the RAF intercepts Russian jets before they enter UK airspace, defined as 12 nautical miles from the coast.
The defence chief also stressed the growing importance of drones and autonomous systems in future warfare. His remarks come as the Ministry of Defence has “not yet decided which capabilities, infrastructure and people it requires to transform the armed forces to be warfighting-ready within the budget available”, according to the PAC.
Sir Keir Starmer has insisted the plan will be published before the Nato summit in Turkey, which begins on 7 July. “We’ve been working on that defence investment plan for some time, very closely with our armed forces,” he said on Friday. Knighton expressed confidence that ministers understand the threats and are increasing spending, but added: “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.”
Sir Geoffrey delivered a final warning to the government: “As we still await its publication … I know I speak for the defence interests of the whole UK when I say – this had better be good.”