Radical cleric Abu Hamza and four other terror suspects are expected to find out today if they have won their latest legal move to avoid extradition from the UK to America.
Two judges at the High Court in London heard from Home Secretary Theresa May's QC on Thursday that if they rule in her favour, then that "effectively is the end" of the matter, as no further appeal was available in criminal cases.
Mr James Edie agreed with Sir John Thomas, President of the Queen's Bench Division, that he will be saying to the court "the Secretary of State would be entitled to move instantly".
Sir John said it was the "final court if we refuse permission".
Lawyers for 54-year-old Hamza, a former imam at Finsbury Park mosque in north London, have asked Sir John and Mr Justice Ouseley to continue an injunction preventing his extradition pending medical tests recommended by two doctors.
His QC Alun Jones said an MRI brain scan could establish that he is unfit to plead because of degenerative problems and should not be extradited to face trial on terrorism charges.
Mr Jones said Hamza's health is "deteriorating" and he is suffering from long-term depression, inability to concentrate and short-term memory loss.
Although the court has still to give its final ruling, Sir John suggested in the course of Thursday's argument that, if there was a risk of a degenerative condition, "the sooner he is put on trial the better - I don't conceivably see how a delay can conceivably be in the interests of justice".
Hamza is one of five terror suspects who have launched last-ditch legal challenges at the court after the European Court of Human Rights refused to stop their US extradition.
Mr Jones said the application was not "a device" to avoid removal. Hamza is suffering from long-standing clinical depression as a result of being held for more than eight years in "harsh, utterly unacceptable conditions" in the high-security unit at Belmarsh prison in southeast London.
He is suffering from Type 2 diabetes, extensive psoriasis and sweating as well as the depressive effects of long-term sleep deprivation linked to being woken by prison guards every hour of the night.
Mr Jones said a scan could establish whether he is suffering from some organic, degenerative condition affecting his ability to concentrate on legal proceedings and thus his fitness to plead.
Mr Eadie argued that Hamza's medical condition is long-standing and his application could have been brought earlier in the European Court.
Mr Jones suggested Hamza would have been allowed the test - the only issue currently standing between him and extradition - "if this case was not one of such public notoriety concerning a person who has become a pantomime villain".
The judges are also due to give their decisions today in applications brought by terror suspects Babar Ahmad, Syed Ahsan, Khaled al Fawwaz and Adel Abdul Bary.