In an unexpected twist, however, Rashid Rauf may be extradited to the U.K. on an unrelated murder charge. But once in the U.K., British law prevents authorities from charging or even questioning Rauf about the alleged airliner plot.
Rauf, a British-Pakistani, denies any connection to terrorism, though he was named in British press reports and by U.K. intelligence sources as one of the key figures behind a plot to smuggle liquid explosives on board airliners bound for the United States.THE BLOTTER RECOMMENDS
It was Rauf's arrest in Pakistan in August 2006 that led police in Great Britain to call off a surveillance operation and to swoop in on an alleged al Qaeda cell whose members were said to be well-advanced with preparations for the potentially deadly operation which could have killed hundreds if successful.
The public revelation of the alleged plot led to unprecedented new security measures at airports worldwide, most of which remain in force.
Rauf has been held without trial in Pakistan since his arrest, but last week a court there ordered that he be released after the prosecution withdrew the case against him.
The Crown Prosecution Service (CPS) in Britain says that Rauf, who is a dual national, is now expected to be returned to London on an extradition warrant.
A spokeswoman for the CPS said Rauf would be returned as a murder suspect in an unrelated case on a warrant issued by police in the West Midlands area, and that he could not be charged or questioned about the airline plot.
"You cannot extradite someone for one offense and then question or charge them with another," she said.
Rauf is wanted in connection with the death of his uncle who was found dead in 2002 shortly before Rauf left the country to live in Pakistan.
Under controversial British law, which is currently a matter of hot debate by lawmakers in the Houses of Parliament, once a suspect is charged with an offense, he cannot be questioned any more by police. This meant, she said, that even if Rauf is charged with the West Midlands murder, he could not be questioned about the airline plot.
Rauf's lawyer, Hashmat Habib, told the Blotter on ABCNews.com that the extradition proceedings are illegal.
"Pakistan and the U.K. have no extradition treaty so they were ignoring the law of the land," said Habib.
Eleven people, aged 19 to 35, are awaiting trial in London for their alleged part in the airline plot.
Identified by some as an important connection between al Qaeda leaders in Pakistan's wild frontier regions and young British-Pakistani militants in England, Rauf has been a figure of deep controversy in intelligence circles.
Rauf's arrest in Pakistan was regarded by U.K. intelligence as premature, causing the police to swoop in on the suspected plotters in England earlier than planned.
And, according to U.K. sources, some British officials at first blamed the CIA or FBI, who had been told about the ongoing surveillance, of engineering Rauf's arrest in Pakistan and so forcing the hand of British authorities.
"There were some real suspicions and acrimony across the Atlantic about this," said one source, adding that relations were eventually patched up. "We realized the Americans acted in good faith; Rauf's arrest in Pakistan proved to be a pure coincidence."
*Stephen Grey is the author of "Ghost Plane: The True Story of the CIA's Rendition and Torture Program" (St Martin's Press). He is an award-winning investigative reporter who has contributed to the New York Times, BBC, PBS and ABC News among others.