Shaker Aamer was volunteering for an Afghan charity before he was captured by bounty hunters – 13 years later and he's still in Guantanamo

I'm fighting for Shaker's release because he deserves to be with his family in London

Shaker Aamer with two of his children (PA)

Held without charge, in 2002 Shaker Aamer – a Londoner with a British wife and four British children – was put into Guantánamo Bay. Five years later, he was cleared for release.

Unbelievably, he still remains there today, and is the last British resident to be held in the camp. Yesterday, MPs called on the US to release him. “Justice is colour blind, it is creed blind, it should apply to everyone," said the former Tory cabinet minister Andrew Mitchell; "and it is not applying to Shaker Aamer and it is up to the House of Commons to give voice to this view."

The welcome intervention of Parliament, however, came alongside disturbing revelations yesterday; it’s emerged the US might have attempted to negotiate Shaker’s transfer to Saudi Arabia, where he was born before moving to London for 20 years, during which he received permanent residency.

If this is true, then Obama would be breaking his recent promise to David Cameron that the US would “prioritise” Shaker’s return to Britain. And if a transfer to one of the world’s most repressive states goes ahead, then it's likely that no-one will ever hear from Shaker again.

And if the reports are accurate, it begs the question: why would the US government choose to send Shaker to Saudi instead of the UK – the country that has repeatedly called for his return? The fear is that he has not been returned because of what Shaker has seen; because certain officials are terrified at what a free Shaker Aamer will have to say.

Shaker says he was grabbed by bounty hunters in Afghanistan during the chaotic aftermath of the 2001 US bombing. He had travelled to the country to volunteer for a children's charity. But at the time of the American invasion, impoverished locals could earn life-changing sums of money by handing over Arabs like Shaker. Truth, justice, and innocence were usually irrelevant: all that mattered to them was the reward.

After he was captured, Shaker was one of the first men held at the US’s notorious prison at Bagram – the largest US military base in Afghanistan, and one of the grimmest torture sites of the ”War on Terror“. While there, he claims to have witnessed the abuse of numerous others at the hands of US forces. He also says that he saw occasions where visiting UK agents got involved.

For the last 13 years Shaker says that he has been tortured, force-fed, beaten up, held in punitive isolation for months on end, and, subjected up to eight times a day to "Forcible Cell Extraction" (FCE). These are particularly grim. An armed riot squad storms a prisoner’s cell and hauls him by an overwhelming show of force to wherever it is the prisoner is said to have refused to go.

The US is known to record FCEs, so there exists incontrovertible evidence of Shaker’s abuse – if the UK was minded to ask to see them. Sadly, our Government has expressly declined to do so, and claims to credit US "assurances" that all is well in Guantánamo. As someone who has seen recent FCE tapes in another case, I can categorically state that these assurances are false.

Shaker Aamer has never been charged or tried with an offence (PA)

After 13 years of hell in Guantánamo, it is unconscionable that Shaker should have to endure more. An independent medical evaluation found in 2013 that if he is ever to recover from his ordeal, he urgently needs to be returned home. And beyond his physical damage, his wife needs her husband; his kids need their father.

None of this should be beyond David Cameron. In the last 12 months, we’ve seen a welcome wave of releases from Guantánamo. Of these, 30 underwent complicated resettlement processes in host countries from Uruguay to Kazakhstan. It is impossible to see why the US is able to arrange these transfers, but has not returned Shaker – a cleared man – back to its British ally.

The children of Shaker Aamer, pictured in 2012 (Jason Alden)

MPs are right to ask the Government to dispense with its excuses. Given that he has already been cleared, and the UK has openly sought his return, what could justify his continued confinement – much less his forcible transfer to Saudi Arabia to be permanently silenced?

If the special relationship is to mean anything, David Cameron must make clear to the US that shady deals and forced transfers to other countries will not stand. Shaker belongs with his British family. If the Prime Minister cannot achieve the release of one cleared man held by our closest ally, then what hope is there for the next Shaker Aamer?