Imprisoned Emirati academic Nasser bin Ghaith has been on hunger strike for more than 45 days, according to activist groups.
The economist, who taught at the Abu Dhabi branch of Paris-Sorbonne University, is serving a 10-year-sentence handed down in March 2017 for tweets critical of the UAE authorities.
Bin Ghaith is being held at the Al-Razeen maximum security prison in Abu Dhabi, which is home to a number of Emirati dissidents, and where he claims to have experienced torture at the hands of Emirati officials.
Amnesty International has previously reported allegations of torture and sexual harassment at Al-Razeen.
The academic has been on hunger strike twice before over his conviction and the conditions of his imprisonment.
“In the last year bin Ghaith has been regularly beaten by warders, held in solitary confinement and routinely denied access to basic medical care,” said Joe Odell of the UK-based rights group, the International Campaign for Freedom in the UAE.
“As the UK celebrates the release of Matthew Hedges, we must not forget the Emirati academics unjustly detained in the UAE,” he added.
“We urge the British foreign secretary to raise bin Ghaith’s case with his Emirati counterpart, as he did for Matthew.”
Al Jazeera contacted UAE authorities for their response to the allegations but did not receive one.
News of bin Ghaith’s hunger strike comes just weeks after the release of British academic Hedges.
The Durham University researcher was sentenced to life in prison over accusations of spying but was pardoned shortly afterwards, following an international outcry.
Hedges alleged he was tortured and forced to make confessions against his will.
Speaking at the time of bin Ghaith’s sentencing in 2017. Amnesty’s Lyn Maalouf called the court’s decision “ludicrous”.
“The authorities have left no room for doubt: those who dare to speak their minds freely in the UAE today risk grave punishment,” she said.
According to rights groups, the UAE has detained “scores” of human rights activists and academics, often without charge. Many are imprisoned for lengthy periods of time in trials described as “unfair”.
Others imprisoned include Ahmed Mansoor, an award-winning human rights defender who like bin Ghaith, was also convicted for posts on social media, and lawyer Mohammed al-Roken, who was one of 94 reformists imprisoned in 2013.
— ICFUAE (@ICFUAE) December 11, 2018