British police said on Friday they had arrested a teenager on suspicion of terrorism offenses following the discovery of a "suspicious item" on a London underground train.
Officers used a stun gun during the arrest of the 19-year-old in north London who was detained on suspicion of preparing terrorism acts. Police said they were not looking for anyone else at this stage.
The suspect item, which is still being examined, was found on a train at North Greenwich station, near the Canary Wharf financial district and close to the O2 music venue, on Thursday morning.
Bomb squad officers carried out a controlled explosion to make the item safe and the station and the Jubilee underground rail line were closed for hours while the police carried out their inquiries.