Level 3, the supposedly secure back bone provider, has lost all services at its Braham Street data centre thanks to a robbery.
The company refused to speak to The Register this morning, but many of its customers have been in touch.
According to Level 3 customers thieves got into the building on Braham Street, E1, and stole core router cards.
An email sent by Level 3 to its customers said only: "There was a security breach in our Braham St gateway early this morning. A number of service affecting cards were removed without authority from live equipment. This has resulted in the loss of IP and voice services to a number of customers at Braham St. We are currently attempting to restore service as quickly as possible. We will issue further updates as information becomes available."
We were told no spokesperson was available or likely to be available.
Other technology companies hit by the downtime include easyspace.com.
The theft has raised fears that data centres and large IT departments in the City of London could be the target of an organised gang - last month Easynet's centre on nearby Brick Lane suffered a similar robbery.
In other news BT Broadband suffered a major failure last night.
A spokesman for BT told the Reg: "About 100,000 BT Retail customers lost access late last night but normal service has now been restored. There was an authentication problem with our servers and it was not related to events at Level 3." ®