British Islamic State (IS) hostage John Cantlie twice tried to escape his captors and suffered "weeks and weeks" of punishment as a result, a freed IS captive has said.
Spanish journalist Javier Espinosa, who was held by the radical Islamists between December 2013 and March last year, said Mr Cantlie and American James Foley had failed to flee on two occasions, with Mr Foley once giving up an opportunity to get away when his friend got caught.
The 43-year-old British photojournalist, who has been held captive for over two years, has appeared in multiple propaganda videos for the extremist group, often dressed in an orange jumpsuit and sat behind a desk.
Meanwhile, Mr Foley, 40, was the first of several hostages to be beheaded in a video posted online by the militants last August.
Mr Espinosa, a correspondent for Spanish newspaper El Mundo, wrote in the Times: "Foley and Cantlie tried twice. The first was a failure before it started. They were caught trying to get off their handcuffs with a skeleton key they made.
"On the second occasion, the American showed his true humanity. After getting out of the room where the prisoners were, he had to wait for Cantlie who was to escape second. The guard saw that Cantlie (had freed himself) and Foley could have tried to escape on his own, but gave himself up. 'I couldn't leave John on his own,' Foley said.
"The attempts by Foley and Cantlie caused them weeks and weeks of punishment. Blow after blow. Attempted drownings. More blows. 'They were literally trying to kill us for weeks until they realised that we had given up trying to escape,' Cantlie had said."
The details of the escape attempts follow hints by Mr Cantlie himself that he had suffered waterboarding - a torture technique associated with the US Central Intelligence Agency - in one of the videos released by IS.
In the fifth episode of the propaganda films entitled Lend Me Your Ears, released in November, Mr Cantlie said: "Now, unless we tried something stupid like escaping or doing something we shouldn't, we were treated well by the Islamic State.
"Some of us who tried to escape were waterboarded by our captors, as Muslim prisoners are waterboarded by their American captors."
He last appeared in a documentary-style production titled From Inside Halab, the ancient name for the Syrian city of Aleppo, reporting on a range of topics including education, drone strikes and Sharia law.
The hostage seems well in the film released last month, appearing dressed in black trousers and a brown coat.
Mr Cantlie's father Paul, 80, died from complications following pneumonia last year. His sister, Jessica Cantlie, has previously appealed for ''direct contact'' with the militants holding him.
IS has posted a number of videos of hostages being murdered, including British aid workers David Haines and Alan Henning last year.