"What we have seen from the UK government is outright contempt for Mr. Assange's rights and integrity," Melzer wrote in the report. "Despite the medical urgency of my appeal, and the seriousness of the alleged violations, the UK has not undertaken any measures of investigation, prevention and redress required under international law."
The doctors' letter describes how, over the years, Assange was threatened with arrest if he left the Ecuadorean Embassy in London to seek treatment for a series of ailments, including a cracked molar and shoulder stiffness.
In 2015, a trauma and psychosocial expert who assessed Assange's condition at the embassy concluded that he was suffering from moderately severe depression.
Assange is serving a 50-week prison sentence for jumping bail, imposed after he took refuge in Ecuador's Embassy seven years ago. He faces US espionage charges for publishing classified military and diplomatic documents.
Last week, Swedish authorities dropped a long-running investigation into a rape allegation against Assange after prosecutors concluded that too much time had elapsed since the events in question.
Richard Galpin, a BBC journalist present at Assange's court hearing in October, described the WikiLeaks founder as "frail-looking" and said Assange had struggled to remember when he was born.
Doctors who carried out medical assessments on Assange last year while he was in the Ecuadorean Embassy warned that his time there was "dangerous to his physical and mental health" and a "clear infringement to his human right to health care."
The doctors who signed the open letter to Patel this week said they had done so out of a professional duty to report suspected torture.
"We wish to put on record, as medical doctors, our collective serious concerns and to draw the attention of the public and the world to this grave situation," the wrote.
Written by: Ceylan Yeginsu
© 2019 THE NEW YORK TIMES