Daniel Khalife escaped this morning.
The 21 year old is awaiting trial, accused of terrorism offences and breaching the Official Secrets Act.
He is 6ft 2ins and was last seen wearing a white T-shirt, red, white chequered trousers and brown steel toe cap boots.
He has links to Kingston and officers say he is “most likely” still in the London area.
Commander Dominic Murphy, Head of the Met’s Counter Terrorism Command said: “We have a team of officers who are making extensive and urgent enquiries in order to locate and detain Khalife as quickly as possible. However, the public can help us as well and should anyone see Khalife, or have any information as to where he might be, then please call 999 or the immediately.
“I also want to reassure the public that we have no information which indicates, nor any reason to believe that Khalife poses a threat to the wider public, but our advice if you do see him is not to approach him and call 999 straight away.”