It is unlikely that terror suspect Abu Qatada would receive a fair trial in Jordan if deported, a tribunal has heard.
Professor Beverley Milton-Edwards, who has studied Jordan's political situation for 25 years, told the Special Immigration Appeals Commission (Siac) that Qatada remained a "controversial" and "prominent" figure in Jordan and because of this a fair trial was unlikely.
The radical cleric, described by a judge as Osama bin Laden's right hand man in Europe, is fighting extradition to the Middle East country where he was convicted of terror charges in his absence in 1999.
Milton-Edwards said: "In my view I don't believe there is any credible evidence that the state security court has engaged in a significant amount of reform to have any confidence of him having a fair trial.
"In my view looking at the evidence...it's unlikely that he will be acquitted."
Echoing human rights experts, Professor Milton-Edwards said the country's human rights compliance has not improved over the years, adding: "Jordan has a very, very poor record of human rights compliance.
She explicitly countered Theresa May's legal argument for deporting Abu Qatada. The Home Secretary has pointed to changes in the Jordanian constitution showing that evidence gained through torture cannot be used in a court of law.
"In fact there has been a rollback rather than an improvement (of human rights compliance)," Milton-Edwards said.
"I haven't been able to find credible evidence...of any change.
"This is an unprecedented period of instability."
She said authorities in the country could view Qatada's "symbolism" as an Islamist as a threat to the current regime.
"He still remains a prominent figure," she said.
"(He could be viewed as a) threat in terms of his symbolism and what he could potentially do on his return.
"In many respects Jordan is another police state."
The 51-year-old is facing a retrial on terror charges after Home Secretary Theresa May was given assurances by Jordan that no evidence gained through torture would be used against him.
Lawyers for the Government have told the hearing that he is "scraping the barrel" in the appeal against his deportation.
Qatada, who is said to have wide and high-level support among extremists, featured in hate sermons found on videos in the flat of one of the September 11 bombers.
He has challenged and ultimately thwarted every attempt by the Government over the last decade to put him on a plane.
In December 2001, Qatada became one of Britain's most wanted men after going on the run from his home in Acton, west London.
In October 2002, he was arrested by police in a council house in south London and detained in Belmarsh high-security jail.
Tribunal judge, Mr Justice Mitting, asked Prof Milton-Edwards whether Jordan's memorandum of understanding with Britain to ensure that Qatada will receive a fair trial could be broken.
Prof Milton-Edwards said under the current political and judicial structure it would be difficult to give "anybody" a fair trial despite international promises or widespread publicity of a case such as this one.
"The structural changes necessary for a fair trial in Jordan...means that opportunity for a fair trial in Jordan is deeply prohibited," she said.
"The system is structurally designed to work against the promise."
She said a potential revolution such as those in neighbouring countries during the Arab Spring could also occur in Jordan, which could also lead to the memorandum of understanding being broken.
The hearing has been adjourned until Tuesday.