This is the dramatic moment a bystander was Tasered as police battled to gain control of the frenzied crowd surrounding the scene of a fatal stabbing on London's Oxford Street.
As hundreds of shoppers look on in horror at paramedics trying to revive the teenager outside a branch of Foot Looker in central London, several distressed onlookers appear to try to push past the line of police.
And as emotions run high officers have to physically restrain a number of youths, including one black teen who appears desperate to push through towards the victim following the Boxing Day attack.
