Ofcom has opened formal investigations into BT and Three after mobile outages this summer left Britons unable to make calls – including to emergency services.
The UK's telecoms regulator said on Monday it is examining whether the two operators failed to meet their regulatory obligations after widespread call service disruptions affected millions of users.
According to Ofcom, BT notified the watchdog of a software issue on July 24 and 25 that knocked out mobile call services on its EE network nationwide, preventing BT and EE customers from connecting calls to other networks or reaching 999.
Three separately reported a June 25 incident – just weeks after it merged with network giant Vodafone – that also disrupted voice services and access to emergency lines across its network.
Under the terms of their licences, mobile operators must take "appropriate and proportionate" steps to identify and mitigate risks to network availability and performance, and to prevent or remedy any adverse effects when things go wrong.
The regulator says its investigation will establish the facts and assess whether there are reasonable grounds to believe BT and Three breached these duties.
A spokesperson for Three told The Register it "experienced disruption to voice services following an exceptional spike in network traffic triggered by a third-party software configuration change." Three added that it has "engaged openly with Ofcom and will continue to cooperate fully with their investigation."
BT did not immediately respond to The Register's questions.
The investigations come amid heightened scrutiny of UK networks after a string of high-profile failures. Ofcom fined BT £17.5 million in July 2024 after a failure of its 999 emergency call handling service left thousands of calls unconnected during a June 2023 outage, and Three was previously slapped with a £1.9 million fine for failing to ensure uninterrupted access to emergency services due to vulnerabilities in its network.
Past form suggests these probes could yet end with fines if Ofcom concludes the operators fell short, but for now, the watchdog's latest action underscores once again that even the giants of UK telecoms aren't immune from regulatory scrutiny when their networks wobble at scale. ®
Source: The register