The threats facing the UK exceed those seen at any point since the Cold War, according to the head of the armed forces.

Chief of the Defence Staff Sir Richard Knighton described the present moment as the most dangerous period he has encountered while speaking on BBC Radio 4's Today programme.

Russia continues to test British defences through probing actions that raise stakes and could breach a critical threshold, he noted.

The Strategic Defence Review issued last year functions as a call to action, shifting focus from brief conflicts toward readiness for extended wars of the kind unfolding in Ukraine.

Publication of the Defence Investment Plan is anticipated within weeks following multiple postponements. The document will outline funding for equipment and infrastructure across the coming decade and was initially planned for release in autumn 2025.

Prime Minister Sir Keir Starmer confirmed the plan would appear ahead of a Nato summit in the near term.

Sir Keir stated that the plan has involved close work with the armed forces and stressed the need to increase defence spending while accelerating delivery.

Sir Richard added that ministers must navigate difficult trade-off decisions to meet these demands.

Activity by Russian long-range aircraft in the High North has matched 2025 levels during 2026, with these strategic planes venturing far into areas near UK airspace.

The RAF conducts intercepts of such aircraft approaching the boundary, yet no recent instances of Russian military planes entering the 12-nautical-mile UK airspace zone have been recorded.

Sir Richard addressed the evolution of warfare, noting that drones and autonomous systems will grow increasingly central to future operations.

He emphasized that the risks and threats to the UK surpass anything experienced since the Cold War and called for society to acknowledge this reality, which could require altered priorities and choices.

Russia is challenging traditional military defences alongside non-traditional methods including cyber operations, sabotage and assassination attempts.

Such actions show Russia raising the stakes and risking a line being crossed, he said.

In an April speech Lord Robertson warned that UK security faces peril and accused the government of corrosive complacency on defence matters.

The former defence secretary, now a government adviser, stated in his address that Britain cannot rely on an ever-expanding welfare budget to protect itself.

He described the country as under-prepared, under-insured and under attack, with national security in peril.

Lord Robertson further highlighted corrosive complacency in Britain's political leadership.

Downing Street responded that spending targets have been set, with the defence budget already reaching record levels and set to rise further.