BT has admitted it still does not know how many vulnerable customers are affected by the digital landline switchover, as it delayed the plan because of safety concerns. Ministers last year ordered telecoms companies to pause the rollout of internet-only landlines after a number of serious incidents where so-called “telecare devices” – personal alarms designed to be activated in a health emergency or after a fall – failed because of the switch. BT on Monday said it has resumed moving customers from copper landlines to the new digital network and outlined a new timetable for the programme. However, it warned there was still a lack of clarity over exactly how many elderly and vulnerable customers were at risk, blaming a lack of information from care providers and local authorities. It said that just a quarter of these organisations had disclosed which phone lines have telecare devices on them and urged the rest to follow suit. It is estimated that around 1.8 million people across the UK rely on telecare devices for urgent medical care, roughly 1.2 million of whom use BT’s network. Howard Watson, chief security and networks officer at BT, said: “Managing customer migrations from analogue to digital as...