Britain is not ready for modern war, and time is running out to fix it

Juliet Reingold, a partner at Simmons & Simmons who heads the firm’s defence team, and said the collapse of the “Pax Americana” security umbrella means the UK can no longer rely on legacy alliances and must instead take greater responsibility for its own security.

Writing exclusively for LBC Opinion, Reingold argued that a rapidly shifting global landscape, driven by emerging technologies, new theatres of conflict and evolving threat vectors, demands a fundamental transformation of how Britain approaches defence, security and resilience.

Her warning echoes remarks made by Mark Carney at the World Economic Forum Annual Meeting 2026, where he said the “Old World Order” was over.

Read more: Falklands without key air defences as Argentina spends millions on fighter jets

Read more: British Army takes ferry to Nato exercise - as calls grow for urgent defence spending boost

Reingold said the UK must now adapt to a “multipolar world” in which readiness extends beyond traditional military capability to include industrial strength, digital resilience and civilian preparedness.

“The first duty of government must be to protect its citizens,” she wrote, adding that defence has become an “unavoidable priority” that requires immediate political focus.

She warned that the challenge is not just the scale of investment required, but how effectively it is delivered. Despite rising defence budgets, longstanding issues such as slow procurement, fragmented supply chains and limited industrial capacity risk undermining the UK’s ability to respond to emerging threats.

“To deliver credible and timely capability, the Government must solve a gridlock of interlinking priorities,” she said, pointing to the need to define future battlefield requirements, accelerate procurement, scale industrial output and mobilise both capital and workforce.

Reingold also highlighted the paradox at the heart of defence spending, where governments must commit vast resources to build capabilities intended to deter conflict rather than be used.

She called for a “market reset” to unlock what she described as unprecedented levels of investment into the defence ecosystem, backed by bold policy decisions and closer collaboration between government, industry and investors.

Among her key recommendations were the adoption of faster and more flexible procurement models, greater support for domestic manufacturing capacity and stronger partnerships between major defence contractors, smaller firms and technology innovators.

She also urged ministers to prioritise sovereign capability in critical materials and systems, reducing reliance on foreign-controlled supply chains, while continuing to upgrade legacy platforms to maintain operational effectiveness.

Reingold argued that defence investment could also deliver wider economic benefits, supporting skilled jobs, regional manufacturing and growth in sectors such as artificial intelligence, cyber and advanced engineering.

However, she warned that without structural reform, increased spending alone would not be enough.

“Protecting our citizens will depend on transforming the frameworks that shape investment, innovation and collaboration,” she said.

Her comments come amid growing concern among defence and security experts that the UK and its allies are struggling to keep pace with the changing character of warfare, particularly in areas such as cyber conflict, autonomous systems and the militarisation of emerging domains like the Arctic.

Reingold said success would depend on government and industry adapting their approach to risk and working more closely together, learning from ongoing conflicts and responding more quickly to the needs of front-line forces.

“The ambition is clear,” she said. “The question now is whether we can deliver at the speed and scale required.”