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Internet attack: BBC's Rory Cellan-Jones explains

27 March 2013 Last updated at 17:16 GMT

The internet around the world has been slowed down in what security experts are describing as the biggest cyber-attack of its kind in history.

A row between a spam-fighting group and hosting firm has sparked retaliation attacks affecting the wider internet.

David Emm from Kaspersky Lab and the BBC's Rory Cellan-Jones examine what the implications are for web users.