BT reports £3 billion benefit from digital network migration across UK critical infrastructure

BT has published an economic analysis conducted by Assembly Research that assesses the transition from analogue to digital infrastructure within the United Kingdom's critical national infrastructure (CNI) sectors. The study projects a net economic benefit of £3 billion across five sectors by 2040.

The analysis addresses operational and financial considerations by examining costs, risks, and benefits associated with upgrading systems in energy, water, health (NHS), emergency services, and local government. The report accounts for both upgrade expenditures and rising maintenance challenges tied to legacy networks such as the Public Switched Telephone Network (PSTN) and 2G mobile network, which have experienced a 45% increase in resilience incidents, according to Ofcom data.

Technical findings detail potential efficiency and environmental gains, including reductions in emergency service callouts, staff hours saved, and carbon emissions avoided. Specifically, the research highlights avoidance of 750,000 ambulance trips, 12 million council staff hours freed, over 600,000 NHS staff hours saved, 280,000 false fire service callouts prevented, and 3.42 megatonnes reduction in carbon emissions, equating to the annual power consumption of all homes in Birmingham.

The scope of projected sector benefits encompasses a £1.4 billion saving for the energy sector via enhanced resilience and demand forecasting, £771 million efficiency improvements in water through network monitoring and electricity use reduction, and £486 million gains for local governments by modernising telecare and reducing legacy equipment costs. NHS enhancements include improved call handling and emergency response, while emergency services may experience fewer false alarms and better call management.

Jon James, CEO of BT Business, said, “This research sends a clear message: delaying the shift to digital carries a real cost to public services, the environment and the wider economy. Legacy systems are becoming increasingly unreliable, and the case for action is urgent. BT is committed to guiding the UK’s critical national infrastructure sectors through this upgrade with the resilience and support they need.” Matthew Howett, Founder & CEO of Assembly Research, said, “For the first time, we lifted the lid on legacy network migration and worked to understand the scope and scale of how key UK industries are still relying on aging fixed and mobile networks. Our research found that while the energy and water sectors are already well into their migrations, it’s vital that others follow to avoid growing costs and missed efficiencies.”

The transition from analogue to digital connectivity constitutes a national infrastructure programme involving collaboration between the UK telecommunications industry, Ofcom, and government entities. The PSTN is scheduled for full retirement in January 2027, with recommendations for businesses and public services to complete migration by the end of 2025. In 2024, BT migrated almost 300,000 legacy PSTN business lines. Compared to Germany, Spain, Italy, Portugal, and France, which are further along with network migrations, the UK faces a risk of delay unless migration efforts accelerate.