Thousands of Three mobile phone customers were left without service following an issue with the network.
Tracking website Down Detector recorded a spike of around 2,000 complaints just after 9am on Wednesday morning.
According to the outage tracker, the issues affected customers across the UK, in cities including London, Glasgow, Liverpool, Bristol and Birmingham.
The outage affected customers across the UK, in cities including London, Glasgow, Liverpool, Bristol and Birmingham.
A Three UK spokesperson told the Evening Standard: “We are aware of an issue with the network and are working hard to fix it.
"We know how vital communications are at the moment and are sorry for any inconvenience caused.”
Three later confirmed services had been restored for affected customers.
"We apologise for any inconvenience caused by the issue," said the spokesperson.
Frustrated customers took to social media to share their issues with the Three network.
One social media user said their "iPad was unable to connect to anything".
The outage came at a time when thousands of people across the UK are still working from home during the coronavirus pandemic.
One customer complained it was becoming "impossible to work from home" with no service.
She added: "This is becoming more and more common."
