Video shows 2011 London arrest of Elsheikh and Kotey

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Alexanda Kotey and El Shafee Elsheikh were part of a group that was arrested in Marble Arch after reports of a stabbing in 2011 - but released without charge.

They later travelled to Syria to form part of the Islamic State 'Beatles' group.

Hostages freed by the terror cell told British police the men had boasted of being arrested at a London demonstration years earlier.

Officers identified the protest and recovered video of the two being arrested.