An investigation has been launched into BT after emergency service phone lines were disrupted at the weekend.
Ofcom announced it was opening the investigation on Wednesday, following the UK-wide issue on June 25.
Police, fire and ambulance services in Scotland and across the UK had asked people not to call 999 due to an issue with the phone line.
Police Scotland said at the time many 999 calls were not connecting and advised people to phone 101 in an emergency until further notice.
On Wednesday, Ofcom said its rules required BT to take “all necessary measures to ensure uninterrupted access to emergency organisations”.
The watchdog continued: “They also require providers to take all necessary measures to ensure the fullest possible availability of calls and internet in the event of catastrophic network breakdown or in cases of force majeure.”
It added that providers are required to take “appropriate and proportionate measures” to identify and reduce the risk of service failures such as the one that occurred.
They must also take measures to avoid adverse effects from such events.
“Our investigation will seek to establish the facts surrounding the incident and examine whether there are reasonable grounds to believe that BT has failed to comply with its regulatory obligations,” Ofcom concluded.
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