Four teenagers 'stabbed police officer in east London'
An undercover Met Police officer was stabbed by a group of teenagers in east London while on an operation, the force has said.
Three boys and a girl allegedly attacked the plain clothes officer in an alleyway near The Bow Bells pub in Bow on Tuesday night.
The officer, in his 40s, suffered three stab wounds and remains in hospital.
A 17-year-old held on suspicion of attempted murder has been released on police bail.
A knife has been recovered from the scene. Scotland Yard said the stabbing was not being treated as terrorist related.
The Met said the group, all believed to be in their late teens, may not have been aware the victim was a police officer.
The teens may also have been involved in another incident outside Devons Road Docklands Light Railway Station, where a motorist was threatened with a knife, the Met said.
The stabbed man, who was with the Met's specialist crime and operations unit, was one of four Met officers injured in separate attacks on Tuesday, BBC London has learned.
One police officer sustained a broken hand and another was punched in the face in different incidents in Lambeth.
Another officer was attacked with a needle in Croydon, south London.
On Tuesday, the Met revealed two officers were attacked by a mob of around 30 schoolchildren in New Cross a fortnight ago.
One of them was punched in the face several times then kicked in the head repeatedly after he tried to search a boy suspected of concealing a knife.