Excerpt:
Vigilante gang attacks could escalate into violence and unrest, police have warned, as Islamic extremists vowed to protect "Muslim areas" from those who "disobey God".
Scotland Yard detectives investigating a series of incidents that were filmed and posted on YouTube are also looking into an assault on a man in his 20s after vigilantes confronted white revellers in Shoreditch, east London.
Police have stepped up patrols in the area amid fears the incidents could escalate further and cause unrest in communities.