Shabazz Suleman is alleged to have manned ribats (fortifications), performed guard duty, and carried out military police patrols for ISIS.
Prosecutors say the 25-year-old received weapons training from the terror group after travelling to Syria from Turkey, having left the UK in 2014.
Suleman was arrested at Heathrow last week after flying back into the country from Pakistan.
He appeared at Westminster Magistrates’ Court on Wednesday, wearing a blue sweater and grey tracksuit bottoms.
Suleman, from High Wycombe, Buckinghamshire, stood in the dock, speaking only to confirm his name, date of birth, and address during the brief hearing.
He was not asked to enter pleas to charges of preparing for acts of terrorism, under Section 5 of the Terrorism Act 2006; membership of a proscribed organisation—namely ISIS—under Section 11 of the Terrorism Act 2000; and receiving weapons training, under Section 54 of the Terrorism Act 2000.
His lawyer, Sanjeev Sharma, made no application for bail and Suleman was remanded in custody by Chief Magistrate Paul Goldspring ahead of his next court appearance at the Old Bailey on Oct. 15.
By Henry Vaughan