BT has apologised after a technical fault led to hundreds of thousands of customers losing their broadband connections.
Internet failures were experienced in many parts of the UK, including London, Glasgow, Sheffield, Coventry and Birmingham.
BT has insisted that yesterday's outage was not the result of a cyber attack and instead put it down to a faulty router.
A spokesman for the firm said: "We apologise to any customers for the inconvenience.
"There is no evidence at this stage to suggest that we were subject to a malicious attack."
Customers turned to social media to report problems at about 2.30pm.
The majority of customers were reconnected approximately two hours after the problem started, while those who were still experiencing issues afterwards were advised to reboot their equipment.