Following enquiries, the teenager has been bailed to return to a south London police station in mid-June.

Statement from East Herts Chief Inspector

Chief Inspector Gerry McDonald said: "We are aware of the arrest that took place in Bishop’s Stortford yesterday evening (Wednesday, May 23) and are liaising with the Metropolitan Police.

"The man remains in police custody at this time and searches at the address in Bishop’s Stortford are now complete.

"At this stage there is no suggestion that there will be any further police activity in the area in connection with this investigation however, anyone who lives locally and feels concerned or worried can contact their local Safer Neighbourhood Team."

An 18-year-old man arrested as part of the investigation in north London on Friday, May 18, was yesterday (March 24) charged with numerous terrorism offences.

Sudesh Mamoor Faraz Amman of Brancker Road, Harrow, has been charged with seven offences of making a record of information of a kind likely to be useful to a person committing or preparing an act of terrorism contrary to Section 58 of the Terrorism Act 2000.