Ask Onix
Regulator launches inquiry into major outages
UK communications watchdog Ofcom has opened an investigation into BT and Three following nationwide mobile service disruptions that disrupted emergency calls and left thousands without connectivity.
Timeline of disruptions
In June, Three customers reported widespread issues making and receiving calls. The problem also affected mobile virtual network operators (MVNOs) using Three's infrastructure, including ID Mobile. A month later, BT and EE customers experienced similar outages.
Ofcom stated the incidents caused "UK-wide disruption," including to emergency services, raising concerns about network resilience.
Operators respond to investigation
Three attributed its June outage to an "exceptional spike in network traffic" triggered by a third-party software configuration change. The company said it had cooperated with Ofcom since the incident and would continue to do so.
"We will cooperate fully with Ofcom throughout the investigation and apologise again for any issues caused by this incident."
BT Group spokesperson
Regulatory expectations and past penalties
Ofcom requires telecom providers to identify risks and prepare for events that could compromise network availability or performance. Companies must also take steps to mitigate adverse effects when disruptions occur.
Telecoms analyst Paolo Pescatore emphasized the critical role of reliable connectivity, noting that while outages can happen despite preventive measures, providers must have clear processes to diagnose issues and prevent recurrence.
Previous incidents have drawn regulatory scrutiny. In July 2024, BT was fined £17.5 million for a "catastrophic failure" in its emergency call handling system, which resulted in thousands of unconnected 999 calls. Three was fined £1.9 million in 2017 after Ofcom determined it could have prevented a service loss for customers.
Industry and government reaction
A government spokesperson reiterated that communications providers have statutory obligations to ensure network resilience. The merged Three-Vodafone entity, now the UK's largest mobile network with 27 million customers, has faced heightened scrutiny since its formation.
Next steps
Ofcom's investigation will assess whether BT and Three took adequate measures to prevent the outages and mitigate their impact. Findings could lead to further regulatory action or fines.
