When he failed to appear at a bail hearing in London on Tuesday, prosecutor Luke Ponte told Westminster magistrates’ court he had boarded a coach to Paris on 27 September.
He added: “He failed to comply with the conditions to surrender his travel documents to police. It’s my understanding that he is no longer in the jurisdiction and that he is currently in Syria.”
Abu Rumaysah, whose birth name is Siddhartha Dhar, is a former member of al-Muhajiroun, an Islamist group proscribed by the government, and one of the founders of Muslim Patrol in east London, where he lived.
He and nine other men, including radical preacher Anjem Choudary, were arrested in September on suspicion of supporting al-Muhajiroun and were bailed.
“What I would say is that I would love to live under the Islamic State, I’d love to live under the Shariah, and I hope that one day Britain gets to live under the Shariah as well,” he said.
“I think it’s very naive of the government to think that they can prevent Muslims from desiring to migate there and live under Islam peacefully.
“I think it’s in the interests of the government to allow ctizens in this country to migrate to places where they want to. It’s better for them to do that than to allow them to go underground and off the radar.”
Asked if he wanted to train as a fighter, he said: “I can’t really speak on that because if I were to say something that would promote terrorism or promote anything that would indicate I am supporting terrorism, I would be arrested.”