This comes as, in July, BT and EE customers were unable to make or receive mobile calls to other networks or to emergency services due to a software issue causing UK-wide disruption, which the telecoms giant reported to the regulator.
Separately, Three notified Ofcom of an incident on 25 June that caused a UK-wide disruption to call services, including customers’ ability to contact emergency services.
“Our investigations will seek to establish the facts surrounding these incidents and assess whether there are reasonable grounds to believe that BT and Three have failed to comply with their regulatory obligations,” Ofcom said in a statement.
This comes as the telecoms giants are required to take appropriate and proportionate measures to identify and reduce risks, alongside preparing for any events that could compromise the availability, performance or functionality of their networks or services.
It added that providers must also take appropriate and proportionate steps to prevent adverse effects resulting from any such compromises. Where an adverse effect does occur, Ofcom requires providers to take appropriate and proportionate measures to remedy or mitigate the impact.
Companies are also under a legal obligation to report outages to Ofcom when they exceed certain thresholds.
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