Ofcom investigates BT and Three for failing to connect 999 calls

Ofcom is investigating BT and Three over mobile outages which it said had caused “disruption across the UK”, including to emergency services.

Thousands of Three customers reported being unable to make calls in June, while BT and EE customers suffered a similar outage in July.

The regulator said it would examine whether mobile networks did not do enough to prevent the problems.

Three said in a statement it was working with Ofcom. A BT Group spokesperson apologized to affected customers.

“We will co-operate fully with Ofcom throughout the investigation and apologize again for any issues caused by this incident,” they said.

Meanwhile, Three said it had “experienced an outage to voice services following an exceptional increase in network traffic caused by a third-party software configuration change”.

“Since the disruption, we have openly engaged with Ofcom and will continue to co-operate fully with their investigation,” he said.

According to Ofcom, businesses must take appropriate steps to identify risks and prepare for “anything that compromises the availability, performance or functionality of their network or service.”

It said suppliers should also avoid “adverse effects arising from such commitments” and that, when this happens, they should take steps to mitigate them.

“The importance of connectivity cannot be underestimated,” said telecommunications analyst Paolo Pescatore.

“We all demand a strong, reliable connection at home and away.”

He said outages can occur despite “significant efforts” to prevent them, but said there must be “a simple process to identify the problem and learn lessons so it doesn’t happen again.”

In the incidents at the center of Ofcom’s investigation, thousands of BT and Three network customers reported problems with their mobile service.

At the time, Three told customers complaining about problems making and receiving calls on June 25 that it was experiencing “an issue affecting voice services.”

This wasn’t limited to its own network – it also caused problems for customers on networks that take advantage of Three, such as ID Mobile.

A month later, EE and BT customers complained of similar problems.

A government spokesperson said at the time that “communications providers have legal obligations to ensure their networks and services are adequately resilient.”

Operators have previously faced scrutiny for outages or issues affecting people’s ability to make calls or contact emergency services.

BT was fined £17.5m in July 2024 for a “catastrophic failure” of its emergency call handling service which caused thousands of 999 calls to fail to connect.

Three was ordered to pay £1.9 million in 2017 after Ofcom found it could have prevented a problem that caused customers to lose service a year earlier.

It has since merged with Vodafone to form the UK’s largest mobile network, with 27 million customers.