£3bn opportunity in digital network upgrade of UK critical infrastructure  | Computer Weekly

Research from leading UK connectivity provider BT has concluded with the clear message that now is the time to act on upgrading the UK’s critical national infrastructure (CNI) sectors from outdated analogue networks to digital infrastructure, with the financial, societal and environmental benefits of such a move offering the potential to deliver a £3bn net benefit to the economy by 2040.

The study, conducted by Assembly Research, evaluated the costs, risks and potential gains from digital migration across energy, water, health (NHS), emergency services and local government. It accounted for the direct cost of upgrading, as well as the rising expense of maintaining legacy systems like the public switched telephone network (PSTN) and the 2G mobile network – both decades old and increasingly challenging to support. Data from UK comms regulator Ofcom shows that resilience incidents on the PSTN have risen by 45%, underscoring the urgency of change.

The UK’s transition to digital connectivity is a major national infrastructure programme endorsed by Ofcom and the government. The PTSN will be fully retired in January 2027, with businesses and public services urged to complete their migrations by the end of 2025 to avoid last-minute disruption. In 2024 alone, BT migrated nearly 300,000 legacy PSTN business lines. Yet many CNI providers in the UK still rely on ageing analogue systems for critical operations, while other countries are moving faster.

The research showed that digital network upgrades could transform a number of sectors – in particular the NHS, councils, ambulance services, emergency services, the environment and the energy sector – freeing up resources and preventing millions of unnecessary callouts.

For example, the study calculated that 600,000 NHS staff hours and 12 million council staff hours could be freed up, the equivalent of 6,500 staff working full-time for a year. It also estimated that up to 750,000 unnecessary ambulance trips could be prevented, avoiding more than 100 journeys every day. Emergency services are said to have the possibility to avoid 280,000 false fire service callouts by retiring outdated fire alarm systems.

Outside the health sector, the study hinted at £1.4bn in potential savings from improved resilience and demand forecasting in the energy sector, while possible environmental gains cited amounted to saving 3.42 megatonnes of carbon emissions, equal to powering every home in Birmingham, the UK’s second largest city, for a year.

Putting a financial figure on these gains, the study noted that for the energy sector, digital networks could deliver improved resilience, help prevent outages and enable more accurate demand forecasting, translating to an estimated £1.4bn in savings. In the water sector, smarter network monitoring and reduced electricity usage could generate efficiencies worth £771m.

In addition, the study argued that local governments stand to gain £486m by modernising telecare systems and cutting the cost of maintaining ageing analogue equipment. In the NHS, digital transformation promises better call handling and more efficient emergency response. The study added that emergency services could see fewer false alarms and improved call management, enabling faster, more targeted responses.

Jon James, CEO of BT Business, said the results of the study sent a clear message that 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,” he noted. “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 and CEO of Assembly Research, said: “For the first time, we’ve lifted the lid on legacy network migration, and worked to understand the scope and scale of how key UK industries are still relying on ageing 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.”