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.