Ofcom opens investigation into BT and Three over 999-call outages in UK
Regulator probes whether networks did enough to prevent disruptions affecting emergency services amid past penalties and a major telecom merger
Ofcom on Tuesday launched a formal investigation into BT and Three over mobile outages that it said caused UK-wide disruption, including failures in emergency services calls to 999.
The inquiry follows incidents in June and July that affected large portions of the country’s mobile networks. Thousands of Three customers reported an inability to make or receive calls in June, while BT and EE customers faced a similar outage in July. Ofcom said it would scrutinize whether the mobile operators did enough to prevent these problems and to identify and mitigate risks to network resilience.
Three said it was engaging with Ofcom and would cooperate fully with the investigation. A BT Group spokesperson apologized to customers and said the company would cooperate fully with the regulator throughout the process.
Three described its outage as a disruption to voice services caused by an exceptional spike in network traffic triggered by a third-party software configuration change. The company said it had engaged openly with Ofcom since the incident and would continue to cooperate with the investigation. The regulator noted that providers must act to identify risks and prepare for anything that could compromise the availability, performance or functionality of their networks or services and must also prevent adverse effects arising from such compromises, taking steps to mitigate them.
telecoms analyst Paolo Pescatore emphasized the importance of reliable connectivity, saying the outages underscored the need for a straightforward process to identify issues and learn lessons to prevent recurrence. He noted that outages can occur despite significant preventive efforts but urged a clear mechanism for learning from incidents so resilience can improve over time.
Ofcom’s scrutiny comes amid a legacy of telecoms incidents and penalties that have shaped the regulatory landscape. BT was fined £17.5 million in July 2024 after Ofcom found a catastrophic failure in its emergency call handling service, which led to thousands of 999 calls not being connected. Three was ordered to pay £1.9 million in 2017 after Ofcom concluded it could have prevented a similar loss of service for customers a year earlier. Since then, Three has merged with Vodafone to form what is described as the UK’s largest mobile network, serving about 27 million customers.
The government has repeatedly underscored operators’ statutory obligations to ensure network and service resilience. A spokesperson said that communications providers have a duty to maintain resilient networks and services, particularly given the critical nature of emergency communications. The current investigation signals renewed regulatory emphasis on how network operators plan for and respond to outages that threaten public safety and everyday connectivity.
Industry observers note that the ongoing focus on 999-call reliability reflects broader concerns about telecoms infrastructure in an increasingly digital economy. As networks rely more on complex software configurations and interdependent technologies, regulators say the priority remains preventing outages, quickly identifying root causes, and implementing durable fixes that reduce the risk of recurrence. The Ofcom inquiry into BT and Three will assess not only the immediate incidents but also the adequacy of steps taken before, during, and after the outages to maintain service continuity across the country.