Hours after a "faulty switch" took the entire BBC website network offline for an hour on Tuesday night, a row has broken out between the corporation and its IT contractor, Siemens.
The BBC News site reported the outage on Wednesday morning, quoting an internal security bulletin sent to corporation staff by Siemens explaining the cause of the disruption.
The BBC article – which has now been amended to remove all reference to Siemens – paraphrased the memo as: "Or, in layman's terms, they turned it off and back on again."
Siemens executives are understood to have been furious the internal email was published. Choice quotes from the email, which has been seen by MediaGuardian.co.uk, have been replaced by comment from Richard Cooper, the BBC's controller of digital distribution.
The offending email sent by Siemens to BBC staff on Wednesday morning said: "Cause of issue: Faulty Switch ... Services Impacted: Everything."
It adds: "Siemens network engineers remotely powered down equipment at a second Internet connection at Telehouse Docklands. This got things back up and running again.
"They then isolated the core router in Telehouse Docklands, and restored power to it. Once power was restored and the router was running in a satisfactory way, they reconnected to the internet and BBC networks in a controlled manner. Further investigations are ongoing to identify the root cause of this fault."
Siemens' £1.9bn contract with the BBC is thought to be coming to an end. The German engineering giant won the contract after acquiring the corporation's IT unit, BBC Technology, in 2004.
The BBC's decision to sell its technology arm to Siemens was heavily criticised at the time. A report published in 2007 by the House of Commons' public accounts committee said BBC management omitted millions of pounds of hidden costs when encouraging the board of governors to approve the sale in 2004.
Last March, the BBC narrowly averted industrial action by Siemens staff after offering a revised pay plan. Siemens staff working on the BBC contract were balloted for industrial action by the broadcasters' union Bectu over a pay freeze. The deal came after more than 70 redundancies were made among staff working on the BBC contract.
Steve Herrmann, editor of the BBC News website, explained the outage on the broadcaster's editors blog: "Last night, just before midnight, there was a thankfully rare event: a total outage of all BBC websites. We're still investigating precisely what happened, but as I said last night, I promised to keep you updated as we find out more."
The routers which direct people to the site had failed, Herrman explained. He added: "Normally this would not cause any problems as we plan for events like this and run backup equipment.
"But, in an unusual turn of events, these also failed meaning that the whole of BBC Online became unavailable. A number of internal services were also affected."
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