A panel of UN experts and a group of 100 legal and human rights scholars have written to the president appealing to him to pardon the 53-year-old prisoner, the first 9/11 detainee to be tortured at the CIA global network of secret prisons.

“His immediate release and relocation to a third safe country are long overdue,” a group of 12 UN special rapporteurs on arbitrary detention, forced disappearances and other human issues, wrote in their letter to the outgoing president.

“Mr Abu Zubaydah suffers serious health conditions, including from injuries sustained during torture that are allegedly exacerbated by the denial of medical attention. In addition, lawyer-client communication has been seriously impeded,” they said.