Customers with mobile network Three have been hit with widespread outages for a fourth day running.
According to website Down Detector, which tracks user reports of outages, customers began experiencing an issue on the network shortly after 11am.
The firm has said its engineers were doing all they can to fix the issue and apologised to customers.
In a statement on X, formerly Twitter, it said: “Some customers may be experiencing issues with our network this morning. Our engineers are working hard to fix it.
“This issue is also impacting customer service, so please check back here for the latest updates.
“We're very sorry for the issues with service over the past few days and sincerely apologise for any inconvenience caused.”
In a separate post just after 2pm on Monday, Three said: “Following an issue with our network that started earlier, services are now recovering.
“We know a number of our customers are still waiting on their service to be restored, and our engineers are working to fully fix it.”
Our customer services are still impacted and unavailable, so please check back here for the latest updates
We are very sorry for the issues with service over the past few days and sincerely apologise for any inconvenience caused (2/2)
— Three UK (@ThreeUK) February 12, 2024
More than 12,000 customers have reported issues on the network, according to Down Detector, with others voicing their dissatisfaction on social media.
Issues include problems accessing mobile data, a lack of signal, and a “total blackout” were among the complaints raised by customers.
Among the locations reporting the most outages were London, Manchester and Glasgow.
One affected customer said: “I can count on one finger the amount of days I’ve had full service in the past week!”
Another added: “It’s 2024 and my phone network has been completely down for three days. Absolute joke.”
Meanwhile a third said: “Three engineers clearly not working hard enough because it’s down yet again today.”
Three is the fourth-largest mobile network operator in the UK, with about 10.3 million subscribers as of May 2023.
The Competition and Markets Authority (CMA) is to probe whether the deal could harm consumers by leading to reduced choice or higher prices.
If the deal goes ahead, the resulting network will be the UK’s largest, with some 27 million customers.