Question

To ask His Majesty's Government what assessment they have made of the ability of digital landlines and mobile networks to maintain access to emergency services during nationwide power failures lasting (1) 24 hours, (2) 72 hours, and (3) seven days; and whether they intend to publish that assessment before the retirement of the Public Switched Telephone Network on 31 January 2027.

The Government has assessed and published the impacts of National Power Outage (NPO) in the National Risk Register 2026, covering the secondary impact on utilities including Telecommunications networks. The effects would depend on the location, scale and nature of the electricity disruption and the resilience arrangements of individual communications providers

There are statutory obligations on communications providers to take appropriate and proportionate measures to ensure that their landline and mobile networks and services remain available. Ofcom has published Network and Service Resilience Guidance setting out its expectations of providers. For fixed telephone services, providers must offer at least one solution that enables access to emergency services for a minimum of one hour during a power outage at the customer’s premises. The solution must be suitable for the customer’s needs and provided free of charge to customers who are at risk because they depend on their landline. These are minimum requirements, and many providers offer longer battery backup arrangements. Ofcom has also clarified its expectations for mobile network operators’ backup power arrangements in its resilience guidance.

If a customer’s mobile network is unavailable, an emergency 999 call can connect through another available mobile network. This safeguard remains dependent on at least one network being available in the area with sufficient back up power to maintain service for the duration of the outage.

The Government will continue to keep telecommunications resilience under review as industry completes the transition from the Public Switched Telephone Network.