An author researching Shakespeare at the British Library was surprised to find a new online filter had blocked Hamlet for “violent content”.

Mark Forsyth was working on a new tome when he decided to look up the play to check a line.

Writing in his blog, he explained: “I had to quickly check a particular line in Hamlet, so I Googled Hamlet MIT, because the Massachusetts Institute of Technology has put the entire works of Shakespeare up on the Internet. (It takes 70 mins to order a physical book). I clicked on the link and...

“A message came up from the British Library telling me that access to site was blocked due to ‘violent content’.”

Forsyth claims his enquires with staff were met with shrugs and smiles, and that calls with the IT department yielded the explanation that it was the British Library’s wifi service that had blocked the tome..."and that the British Library's wifi system, they seemed sure, had nothing to do with the British Library."

He adds: “Now Hamlet is a violent play. I see that. When the curtain comes down there’s a lot of bodies on the boards. But...”

Following Forsyth’s complaint on 7 August, the British Library tweeted that Hamlet is no longer blocked.

A spokesman for the British Library confirmed the news: "The upgraded service has a web filter to ensure that inappropriate content cannot be viewed on-site.

"We've received feedback from a number of users about sites which were blocked, but shouldn't have been. We're in the process of tweaking the service to unblock these sites."

Professor Ross Anderson, a security expert at Cambridge University tells the BBC the filters are "pointless" and that it was "completely inappropriate" to have one at the British Library.

He added: "Everything that is legal should be available over the library's wifi network. The only things they should block are the few dozen books against which there are court judgements in the UK.

"One of the functions of deposit libraries is to keep everything, including smut."

British Prime Minister David Cameron plans to introduce opt-out internet censorship at service provider level - targeting porn and "sensitive subjects" unless customers specifically ask them not to.

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