UK to hold largest home defence exercise in decades

The United Kingdom will test its readiness for international hostilities affecting the homeland through the largest home defence exercise in several decades in 2027, the Government has announced, as part of an acceleration of Home Defence Planning that has included updating the government War Book.

The commitment was set out by Darren Jones, Chief Secretary to the Prime Minister, in the Government’s first Annual Statement on National Resilience to Parliament, delivered alongside implementation reports on the Resilience Action Plan and the Biological Security Strategy. “We have also accelerated our Home Defence Planning, including updating the government War Book and increasing the emphasis on aligning military and civilian efforts if international hostilities affect the UK,” Jones said, as quoted in the statement. “We will rigorously test these plans through the largest UK home defence exercise in several decades in 2027, to ensure that should the worst ever happen, we will always be ready.”

The War Book, the government’s classified playbook for the transition to war, dates in concept from the Cold War, when successive versions set out how Whitehall would respond to escalating crisis and conflict, and its updating reflects renewed attention to homeland defence at a time of heightened tension with Russia. Jones noted that defence spending will rise to almost £80 billion a year by 2029, describing it as “the biggest sustained boost to defence spending since the Cold War,” and said resilient public services and infrastructure are how the country safeguards its national security.

The statement accompanied publication of the latest National Risk Register, the public version of the classified National Security Risk Assessment, which lists 95 risks in total. Jones pointed to the conflict in the Middle East and Russia’s war in Ukraine as having exposed vulnerabilities in global energy supply chains, and warned that artificial intelligence “not only brings huge opportunities, but threats too if it is weaponised by criminals against us,” including novel ways of carrying out hostile cyber attacks against businesses and critical infrastructure. On climate change, he said the risks “cannot be underestimated,” citing record temperatures in May that were exceeded again in June.

A national resilience public awareness campaign will launch later this year to inform the public of what Jones called “the small but important steps they can take to be prepared in case of emergencies and disruption,” whether severe weather or a cyber attack affecting access to power, water, phone signal or food. The Government is also launching a Call for Views on the Civil Contingencies Act 2004, the legislation that has underpinned emergency preparedness across the UK for more than two decades, to gather evidence on where it may need updating, and will publish an Energy Resilience Strategy and a Transport Resilience Strategy later this year.

On biological security, Jones warned that a future pandemic or the use of biological weapons by hostile actors “could permanently scar the UK’s social and economic resilience,” and reported what he described as strong progress over the past year.

That includes the delivery of Exercise Pegasus, the largest Tier 1 pandemic scenario simulation in UK history, the establishment of a Network of National Biosecurity Centres backed by £1.83 billion of investment, Moderna’s new mRNA vaccine manufacturing centre, a Pandemic Preparedness Strategy supported by an additional £1 billion in health protection measures, and the operationalisation of a Biothreats Radar providing real-time data on biological incidents alongside new approaches to monitoring the convergence of AI and biology.