Shaker Aamer tells of brutal treatment at Guantanamo Bay

Former Guantanamo Bay detainee Shaker Aamer has embarked on a campaign for the truth to come out about his 14 years in the notorious military prison and continued to point the finger at British authorities for their alleged complicity.

In a series of interviews since his release in late October, the last British prisoner to be held at the facility has increasingly opened up about his brutal treatment at Guantanamo Bay, likening it to Azkaban, the prison in the Harry Potter novels, and saying it is a place where the Geneva Convention does not exist.

He told ITV News: "Everything that happened to us is a war crime in Guantanamo.

"Everything that is happening right now is a war crime in Guantanamo."

The human body can adapt to the physical pain of torture, Mr Aamer said, but Guantanamo Bay was a place designed by psychologists to "destroy a human being totally".

He said he was forced to drink sewage water during a prolonged hunger strike and there was "no limit" to the interrogation techniques used. This included threats to rape his daughter, he told the BBC's Victoria Derbyshire programme.

Mr Aamer said: "That was completely inhumane.

"It was worse than the beating as well, worse than everything, just thinking of my daughter ... and I just sat there, silent completely.

"And (for) three, four days I didn't say a word."

Speaking about what should happen next as he adjusts to life back in London and gets to know his four children again, Mr Aamer's focus was squarely on "the truth".

He said: "The only thing I really would like to happen is for (former prime minister) Tony Blair and for whoever in the government at that time, is to tell the truth, just like I'm telling the truth to the world."

Mr Aamer told the BBC he was 90% certain an English intelligence officer was present during some of his interrogations. That man, known only as John, did not take part in the violence but made no attempt to stop it, he said.

Mr Blair "definitely" knew what was happening in Bagram, he alleged, adding: "They know, all of them, they know what they were doing.

He added: "If these guys of the head of the state, they don't know, who's supposed to know?"

A spokeswoman for Mr Blair has said he "never condoned" the use of torture.

Mr Aamer, who had allegations of involvement in the Taliban against him dropped in 2007 but was still held in detention, said Guantanamo Bay must be closed.

In his ITV interview, he made a direct appeal to US president Barack Obama, saying such a move would render him a "hero". He added: "If he really wants to establish justice, if he really wants to live by his word, he's not going to need to wait for the whole United States of America to support him."

Mr Aamer said his ordeal was more a reflection on America than the UK, and explained: "Everybody was scared, everybody was doing what America wanted them to do regardless, and some of the intelligence, British intelligence service they told me that openly, 'it's not in our hands Shaker'."

He said Mr Blair and then-foreign secretary Jack Straw should be called before a public inquiry, and suggested they should be granted indemnity in order to "be more open about it".

Mr Aamer said: "I believe nobody should be prosecuted because of what happened in the past, especially if we try and prevent it from happening in the future."

In the wide-ranging interviews, Mr Aamer rejected accusations he knew Osama Bin Laden, but acknowledged that during his time in Afghanistan he may have unknowingly met with people who were consorting with him.

This may have happened because in Kabul it was common to invite people to your house after meeting in a mosque despite knowing "nothing about them", he explained.

Mr Aamer said he admitted to being involved in al Qaida under duress, and his initial decision to move to Afghanistan was because he wanted to feel like he "belonged". Despite living in England as a "very practising Muslim" for five years, he said it wasn't easy.

While admitting his answer would not please everyone, he told the BBC: "It was hard, because people talk and say rubbish things about you, about your wife.

"(There were) eyes chasing you everywhere you go."