Among the first people to speak to on Friday afternoon, after the private jet that flew him from Guantánamo touched down at Biggin Hill airfield, south of London, were a few doctors.
Not far behind them was a small group of lawyers.
They believe that Aamer has a strong claim against the British government and its security and intelligence agencies, MI5 and , not just because of any role they played in his incarceration, but because of the way in which they interrogated him despite being aware that he was being mistreated while in US hands.
Claims brought previously by British nationals and residents who were locked up at the US prison – men such as Binyam Mohamed and Moazzam Begg – have already been settled by the British government for undisclosed sums, thought to run to millions of pounds.
Aamer, who was consigned to Guantánamo in February 2002, having previously been held and allegedly tortured at the US prison at Bagram, north of Kabul in , is expected to have an even stronger case.
One of the allegations that will form the basis of the claim is that a British intelligence officer was present while Aamer was being tortured at Bagram.
He has also told his lawyers that while at Bagram he witnessed the torture of another inmate, Ibn al-Shaykh al-Libi, whose forced “confession” that al-Qaida had links with Saddam Hussein’s regime was cited by the Bush administration as justification for the invasion of Iraq.
Also waiting in the wings, once Aamer has received a thorough medical examination and been reunited with his British wife and four children, may be a team of Scotland Yard detectives. This team has been investigating the involvement of UK intelligence officials and, allegedly, government ministers in the human rights abuses that were committed against terrorism suspects in the years after the 9/11 al-Qaida attacks.
These detectives spent three days interviewing Aamer at Guantánamo in 2013. “They were the first people who had shown him any respect,” said Clive Stafford Smith, one of his lawyers. “He would be more than happy to see them again, if only because they were so pleasant.”
A police file following an investigation into another case, in which two Libyan dissidents were kidnapped in a joint MI6-Libyan operation and flown to Tripoli along with their families, is currently on the desk of the director of public prosecutions, Alison Saunders. She is expected to rule shortly on whether anyone should face charges.
The Yard’s inquiries into the involvement of and MI6 in the abuse of prisoners at Bagram, and the torture of Binyam Mohamed in Pakistan, did not result in any charges.
“Shaker doesn’t want anyone to be prosecuted over his case, although there is a strong case to answer, as nobody could pretend they didn’t know what was happening at Guantánamo when people were sent there to question him,” said Stafford Smith.
“But he does want to get truth out. And that means he wants there to be a full judicial inquiry.”
The last judicial inquiry into the UK’s involvement in the so-called rendition operations that were launched after 9/11 was shelved in December 2013, and its work handed over to the intelligence and security committee, the panel of MPs and peers said to provide democratic oversight of the agencies.
Aamer, 48, was interrogated three times by British intelligence officers while being held at Guantánamo. He alleges that they informed him that they knew he was being mistreated, but said they would do nothing to assist him. He also alleges that the UK government supplied the US authorities with false information alleging that he had links to al-Qaida.
Before being flown to Guantánamo, Aamer was also held briefly at Kandahar in Afghanistan, where he alleges a British man, wearing military uniform with a red beret, questioned him and refused to offer any assistance.
But the allegations concerning his experiences at Bagram will be those that will be most troublesome for the British government.
In a statement to his lawyers, Aamer has said shortly after being flown to Bagram on Christmas Eve 2001 he was dragged into a room crammed with around 10 men, including a British intelligence officer, who began shouting at him in English, French and Arabic.
“I felt someone grab my head and start beating my head into the back wall,” he said, “so hard that my head was bouncing. I later learned that this was a special technique that they used called ‘walling’, but at the time I had no understanding of what they were doing, it was just terrifying. They were shouting that they would kill me.”
Eventually, he told his lawyers, “I said whatever anyone wanted to hear.”