Burka terror suspect Mohammed Ahmed Mohamed is seeking damages from the UK government in a human rights legal challenge involving allegations of torture.
Mr Mohamed, who was the subject of a Terrorism Prevention and Investigation Measure (Tpim), managed to dodge surveillance and disappear by disguising himself as a woman.
The 27-year-old was last seen fleeing a London mosque in the burka on Friday.
He is understood to have received training and fought overseas for al-Shabaab, the Somalia-based cell of the militant Islamist group al-Qaeda.
The Met Police's counter terrorism command, MI5 and the UK's Border Force are looking for him.
Mr Justice Irwin, sitting at London's High Court, handed down an interim ruling in the action he is bringing for compensation - the first ruling on the use of the Justice and Security Act 2013 in a civil claim for damages.
His claim is against the UK's Foreign Office, Home Office, Ministry of Defence and the Attorney General.
He and another man, referred to as "CF", allege British authorities consented to - or acquiesced in - their detention by Somaliland authorities on 14 January, 2011.
The men say British "officers and agents... by their acts and omissions, procured, induced, encouraged or directly caused, or were otherwise complicit in" their detention, assault and mistreatment and torture while they were in Somaliland.
Mr Mohamed launched his damages claim under a cloak of anonymity and was referred to in court papers as "MA".
But anonymity was lifted today following his disappearance.
