More than 20,000 UK homes have been affected by a phone exchange fault.
BT said customers in northern England and part of Scotland were experiencing disruption to their broadband service following a power cut.
Engineers were working to resolve the problem that hit an exchange covering the Edinburgh and Tynecastle area.
A BT spokesman said: "There's an issue with a node in Edinburgh and we've sent our engineers to deal with it.
"It's affecting a significant part of the UK.
"We've diverted engineers to Edinburgh to fix it as quickly as we can."
More than 20,000 UK homes have been affected by a phone exchange fault.
BT said customers in northern England and part of Scotland were experiencing disruption to their broadband service following a power cut.
Engineers were working to resolve the problem that hit an exchange covering the Edinburgh and Tynecastle area.
A BT spokesman said: "There's an issue with a node in Edinburgh and we've sent our engineers to deal with it.
"It's affecting a significant part of the UK.
"We've diverted engineers to Edinburgh to fix it as quickly as we can."