The battle to define presidential powers in the “war on terror” came under renewed scrutiny on Thursday when a foreign prisoner held in the US on suspicion of being an al-Qaeda “sleeper agent” asked a court to declare his detention unconstitutional.

Ali Saleh Kahlah al-Marri, a Qatari citizen studying computer science in the US, was arrested in Illinois in late 2001 in connection with the investigation into the September 11 attacks. He was slated for a criminal trial in 2003 on charges including credit card fraud.