Question

To ask His Majesty's Government, in light of the National Risk Register identifying a malicious cyber attack on the electricity system as being capable of causing prolonged disruption to telecommunications and other critical infrastructure, what additional resilience measures they have required communications providers to implement to ensure that citizens can continue to access emergency services throughout such an event.

Great Britain has one of the most reliable energy systems in the world, and operators have well-developed plans to respond to and recover from any disruption. The Cyber Security Resilience Bill will further strengthen the UK’s cyber defences and protect more of the essential services people depend on.

Government works in partnership with communications providers to ensure that networks remain secure, resilient, and accessible, including during emergencies and service disruption. There are statutory obligations on communications providers to take appropriate and proportionate steps to ensure their networks and services remain available. Communication providers are required to take appropriate measures to prepare for and reduce the reduce the risks of incidents occurring, and Ofcom have published Network and Service Resilience Guidance that sets out expectations on how providers can meet statutory obligations.

Whilst networks are designed to be resilient, events such as severe weather, loss of electricity transmission, and technical faults can sometimes cause disruption. In these cases, providers must guarantee access to emergency services for at least one hour during a power outage for customers who rely solely on landlines. Although not resilient over days of disruption to services, Battery Back Up Units for broadband services are available free of charge to vulnerable customers or can be purchased from communication providers. In March 2025, providers such as BT, Vodafone, KCOM and Zen Internet announced battery back-up units capable of powering routers for 4–7 hours during a power cut. These measures are designed to prevent disconnection and ensure continued access to emergency services.

If the current mobile network is unavailable, all emergency 999 calls made from mobile phones should automatically switch to an alternative network. This ensures that even if some mobile networks are down or has poor signal, your emergency call can still go through by using another available network.