Hundreds of thousands of BT broadband users may have been affected by what has been described as a "power failure" at a major exchange located in Birmingham.
The BBC reports that much of the UK has been affected, although the number of customers suffering from the downtime has been put at five per cent of BT's total customers, or just under 300,000 based on BT's latest financial figures.
Worryingly, many business users have been without broadband for most of the day, with some saying that they have lost significant revenue as a result.
Since early afternoon when the first reports of downtime surfaced on Twitter, BT advised its customers to "turn their hub or modem off and on again" and around two hours later, many non-commercial customers had started to get their broadband services back.
The company has issued a statement saying that "Some business customers' broadband service may have been affected for a slightly longer period. Should any customers continue to experience difficulty in accessing their broadband service, they are advised to turn their hub or modem off and on again."
The downtime highlights the fact that broadband is now a utility as important to end users as water or electricity and the need for a backup plan for business broadband.