Radical cleric Anjem Choudary was arrested together with a Canadian man; both are charged with being members of a terrorist organization

Two prisoners wearing fake suicide belts slashed guard with homemade knives, wounding him and four other officials who intervened; one is follower of radical cleric Anjem Choudary

Usman Khan, 28, was convicted in 2012 of grave terror charges, served less than half of his prison term before being released early

Jack Merritt, 25, was at prisoner rehabilitation event also attended by terror suspect; video footage shows men with fire extinguisher, tusk, battling with attacker

Following terror attack, former counterterrorism official warns criminal justice system 'playing Russian roulette with lives'; minister vows swift government review of laws