Officers from the Metropolitan Territorial Support Group wearing Nato helmets form a cordon in front of a police van as purple smoke from flare rises into the air during scenes of unrest

people man men woman women police officer policeman policemen policewoman policewomen territorial support group riot nato helmet luminous yellow jacket uniform blue line stand form cordon unrest conflict clash outside gates downing street whitehall london england great britain uk united kingdom purple smoke distress flare lapels pixie van truck public order law