David Cameron
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David Cameron: Web firms 'must do more' over extremism

The Intelligence and Security Committee (ISC)'s report into the murder of Fusilier Lee Rigby suggests there was a "significant possibility" MI5 could have prevented the attack had its agents been aware of an online exchange between Michael Adebowale and a person codenamed Foxtrot in December 2012.

Prime Minister David Cameron, speaking in the House of Commons, outlined his concerns.

He said web companies had a responsibility to put in place methods of discovering, and reporting extremist material.