Joe Biden is under growing pressure to use his last week in office to free Abu Zubaydah, a Palestinian detained 23 years ago in the aftermath of the 9/11 attacks and held without charge in Guantánamo Bay.

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.