Mr Aamer denies this saying he was engaged in charity work."
What will be shocking to many, if proved correct, is the accusation that British intelligence, that is MI5 and MI6 personnel, supplied knowingly false information to the US authorities.
Whilst being held in Afghanistan Mr Aamer was allegedly "subjected to cold water treatment, hog tying [and] sleep deprivation". There are also allegations of brutality carried out in the presence of British Intelligence officers. You can read more about the allegations at the BBC here.
Campaigners have worked hard to free Mr Aamer; some celebrities joined the campaign undertaking hunger strikes in support.
But although Mr Aamer was cleared for release by President Bush in 2007 and President Obama in 2009 he remains a prisoner. Obama has pushed to close Gitmo and many prisoners have been released but Guantanamo Bay remains an ingrained stain on US history and situating it away from mainland America changes nothing.
Mr Aamer's children pictured in the image above are now grown.
If you ever wonder why there is so much hate directed against the west consider Gitmo and the plight of Mr Aamer.
On 17 March 2015, MPs debated a backbench motion calling for the release of Guantanamo detainee Shaker Aamer-check the footage here to see how few MPs participated