YouTube, the world's largest video-sharing Web site, this week removed over two dozen videos glorifying gangs and gang violence which had been on its Web site in some cases for over 18 months.

Following a Times investigation into harmful and inappropriate material on YouTube, the Web site took down 30 film clips, most shot in grainy video showing hooded youths brandishing illegal weapons such as machetes, hand guns and even sub-machine guns.

Google admitted they were clearly in breach of its own user guidelines, which had recently been revised to deal with gang videos.

Google's head of communications in Britain, former TV journalist Peter Barron, said that as a result of concern about the use of the Web site by gangs, it had now introduced new guidelines prohibiting users from showing weapons in their videos in order to intimidate people, but that these had only "gone live" on Friday.

He blamed "teething problems" with the new policy for the fact that its own monitors had failed to removed the material after a Times reporter posing as an ordinary user had flagged them up as inappropriate three days after the new policy had been introduced.

"The new guidelines have just been established, clearly it will take a little while for them to feed through the system," said Mr Barron.

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