Every other night Saad Iqbal Madni wakes up screaming. For more than five years the Pakistani Islamic scholar was one ghost among many - Prisoner Number 746 in Guantanamo Bay.
In terror-filled moments, in the dead of night, he still is.
"Since they arrest me, up to today, every second night I wake up screaming, yelling and crying," he said, breaking down in tears.
"I can't forget what they did to me. No one can do that with the animals. I don't know how they can do that with human beings."
In his nightmares, the prize-winning reciter of the Koran is back in "frequent flier status".
"That means the detainee is not allowed to sleep," he said. "Every 20 minutes, every half an hour, the guards come and wake up the detainee, they handcuff him, they leg shackle him, and move him from block to block, cell to cell. If we try to get a nap the guards come and kick the doors, yelling, screaming and cursing."
Much of Mr Madni's chronicle of humiliation, intimidation and torture cannot be independently verified, but his account echoes testimony from other former prisoners.
And his descriptions are forensically detailed.
"The CIA (Central Intelligence Agency) used to joke with me with I had a photographic memory," he said.
The CIA declined to comment on his allegations, but the US defence department told the BBC that detainees are treated legally and humanely in Guantanamo, and that torture has never been used.
Mr Madni - who needs a cane to walk - says he is living proof that it has.
He claims that after he attempted suicide, the torture was stepped up, with six months inside a refrigerated cage.
Addicted to morphine
"They stripped me naked, just allowed was the underwear. They put me inside a six-feet by four-feet cage.
"They turned on the air conditioning to very high. During this period they took me to interrogation, and they said 'OK, now you are going to admit, or not?' I said no. I started a hunger strike because I was suffering too much, and they started giving me codeine and morphine as pain killers."
By the time of his release, Mr Madni says he was addicted to morphine.
His doctor, Lahore-based psychiatrist Muhammed Haris Burki, confirms his claim.
"He was a victim of pharmacological torture," said Dr Burki. "They made him an addict and it took five months to get him off it."
Mr Madni's medical history reads like a psychiatric textbook - depression, insomnia, post traumatic stress disorder, mood swings, paranoia, psychosis and anxiety.
He says that doctors in Guantanamo told him they saw him as an enemy not a patient.
He claims he was refused treatment for an ear infection and told to co-operate with interrogators if he wanted medical help.
"The way they treated me there I was never hoping to go back alive," he said.
"The doctors over there said 'in three months you are going to die. The infection is close to your brain. Any time you can have a stroke'."
After he went on hunger strike, a US court ruled that he was in "a life-threatening medical condition" and authorised a one-off visit by his lawyers.
Mr Madni's troubles began during a visit to Indonesia, a few months after 9/11.
The CIA was casting a wide net for terror suspects. It was a season of fear, and a new era of extraordinary rendition.
He says he was bundled onto a plane in Jakarta in January 2002, and flown to Egypt - via the British territory of Diego Garcia. Britain admits that two rendition flights refuelled on the island in 2002.
The legal charity, Reprieve, intends to raise Mr Madni's case during an upcoming torture inquiry in the UK.
"In 2002 Mr Madni was rendered to brutal torture through British soil, with the knowledge and complicity of the British government," said Clive Stafford Smith, director of Reprieve.
"Nine years later, the least the country can do is admit that this happened and apologise."
When Mr Madni got to Cairo, Egyptian intelligence agents were waiting. He says they did the dirty work, with US agents looking on.
"The place they put me in was smaller than a grave," he said.
"In 92 days I couldn't lay down comfortably. They asked me questions about [shoe bomber] Richard Reid, and if I had any information about 9/11. When I denied it, they gave me electric shocks in my knees. A few times I passed out."
The next stop was Bagram Air base in Afghanistan where he says he was deprived of food, menaced by dogs, and kept in isolation for 10 months.
In March 2003 Mr Madni was transferred to Guantanamo and classified as an enemy combatant. He was accused of being an al-Qaeda operative, and of planning a terrorist act - charges he denies.
"One year they gave me 15 charges, and the second year they gave me eight," he said, "and then before they released me they dropped the charges."
Mr Madni denies having links with extremist groups in Pakistan or elsewhere.
He admits to having met members of a hardline Indonesian Islamic group - the Islamic Defenders Front - but says he did not know the US considered them to be terrorists.
"I met them as Islamic scholars," he says. "And they met me as a reciter of the Koran."
He denies allegations that he told them bombs could be placed in shoes.
While condemning the loss of innocent life in the 9/11 attacks, he refuses to give an opinion on Osama Bin Laden.
"I can't make comments personally about him because I don't know him," he says.
After a US court ordered his release in August 2008, he returned to Pakistan but it was a cold homecoming.
His own government added him to an anti-terror watch list, and severely limited his movements. Mr Madni is now bringing a court action against the restrictions, which he says, have left him suicidal.
"I am suffering more than I was in Guantanamo Bay," he said.
"If the American court let me free, what's the reason for the Pakistani government to put me in house arrest? I can't work. I can't see my family members. I can't leave the city."
Mr Madni says that for him, there is little difference between Guantanamo and Pakistan.
"Over there is a small cage," he said, "and Pakistan is the bigger cage. That's it."
A longer version of the interview can be seen on Our World on BBC World News at 2030 GMT on Friday and 1030, 2330 on Saturday.