By Arthur Martin PUBLISHED: 15:59 EST, 24 May 2013 | UPDATED: 21:36 EST, 24 May 2013 Radicalised: Michael Adebolajo after the brutal murder Internet giants were last night slammed for refusing to remove extremist websites. Search engines such as Google and Yahoo must do more to shut down hate-filled sites in the wake of the Woolwich attack, MPs said. Thousands of videos which help to radicalise impressionable young men are easily available on YouTube. And within hours of the execution of Drummer Lee Rigby, 25, vile messages praising the attack and encouraging further outrages appeared on Twitter. Police have seized computers since Wednesday’s atrocity and are still investigating if the two fanatics who beheaded the soldier were indoctrinated by online terror videos. Michael Adebolajo, 28, was radicalised by a banned extremist group whose members use the internet to recruit impressionable young men.
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Thousands of videos which help radicalise young men are easily available
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Search engines and social media rely on users to 'flag up' offensive material
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A 31-year-old man was arrested at 9.30pm in London on suspicion of terrorism offences, the charge is not related to the murder of Lee Rigby
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RAF fighters were scrambled over London to intercept a jet
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The family of Drummer Rigby spoke movingly of their love for him
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It emerged that second killer Michael Adebowale was radicalised at university where he met Adebolajo
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More than £500,000 was donated to the Help for Heroes charity
A @placeholder spokesman said: ‘YouTube has community guidelines that prohibit dangerous or illegal activities such as bomb-making, hate speech and incitement to commit violent acts, and we have removed a significant number of videos under these policies.’