6 Things to Know About the UK Emergency War Alert System in 2025

The UK is preparing to test its emergency war alert system for the first time in two years, as officials urge the public to be ready for the possibility of war.

Later this year, all compatible mobile devices across the UK will emit a loud alarm as part of a national test of the ‘Emergency Alert System.’

Originally launched in 2023, the system is designed to provide immediate warnings about serious life-threatening dangers in the area, and this new test follows government concerns that the UK could face a direct threat in a wartime situation.

The test comes amid growing instability in the Middle East, increasing fears about the potential for global conflict involving nuclear-armed states.

In June 2025, Prime Minister Keir Starmer released a new Strategic Defence Review (SDR), outlining the most significant security threats the UK has faced since the Cold War. These include threats from Russia, cyber warfare, and hostile actions from nations like Iran, North Korea, and China.

Key Points About the UK Emergency War Alert System:

1. What a ‘War Alert’ Involves

• Immediate public response: When the alert sounds, phones will temporarily lock until users acknowledge the message. Instructions may include finding shelter, evacuating, or avoiding disruptions.

• Mental preparedness: The system aims to prepare citizens to act quickly in emergencies before other traditional alert methods like radio or TV take over.

2. The Emergency Alert System

• Mobile alerts: All modern 4G and 5G phones in the UK will receive a 10-second, siren-style notification via cell broadcast when there is an imminent threat.

• Background: Introduced in 2023, the system has been tested several times and is known for its startling volume.

• Expanded purpose: While originally intended for civil emergencies like flooding or terror attacks, the system has now been adapted to handle national wartime threats.

3. Terror Threat Assessment

• The UK’s current terrorist threat level, as maintained by MI5 and the Home Office, is at ‘substantial’—indicating that an attack is likely, though not imminent.

• This level reflects rising global tensions, particularly involving Russia and Iran, as well as increased cyber and hybrid threats targeting UK infrastructure.

4. Strengthening National Security

• The UK’s National Security Strategy, updated in June 2025, underscores the need for heightened defence readiness.

• Plans include raising defence spending to 5% of GDP by 2035, conducting large-scale military drills such as “Pegasus,” holding annual crisis simulations, and deploying nuclear-capable F-35 jets.

• Threat scenarios now account for missile attacks, cyber warfare, and direct assaults on UK territory.

5. Community-Level Emergency Coordination

• In areas like Aldermaston—home to the UK’s nuclear warhead facility—residents regularly experience sirens and alerts through a localized community text system.

• The Church of England is also stepping in, preparing faith-based networks to help communities maintain spiritual and emotional resilience in times of crisis.

6. Public Preparedness Tips

• Check device compatibility: Most modern 4G and 5G phones can receive alerts.

• Build an emergency kit: Store essentials such as water, medication, identification, and critical documents in an easily accessible place.

• Stay calm and informed: The alerts are intentionally loud to capture attention, but their purpose is to inform, not to panic the public.