Issues plaguing EE and O2, which saw some customers unable to make phone calls to landlines in the country, have been resolved, the two companies said.
An EE spokesperson told Daily Mail the issue has been fixed:
"Customers of a number of operators have experienced problems calling landlines for a short period. The issue has now been resolved."
O2 also said BT was looking into any problems there may be on the network. It had posted an update on its Live Status Checker webpage:
"We are aware of an issue where some O2 customers may be experiencing difficulties making calls from their mobile to EE mobiles and to landline numbers," the firm said.
"BT, our fixed line partner, have confirmed they are investigating a problem within their network and we apologise for any inconvenience."
Customers took to social media, reporting issues when calling from a mobile network to landlines. Others said the problems were much greater, and reported complete signal loss.
BT later said it had found no evidence that it had a problem within its network. O2 added that it will continue surveillance over the network to make sure no new stability issues appear.
Yesterday, the two companies confirmed there were problems connecting to landlines, after people started complaining on social media.
An EE spokesman tweeted: 'We're aware customers from EE (and other networks) are having issues calling landlines. We're investigating urgently.' EE also said this was a ‘severe outage’.