In a phone call, the-22-year-old proved he was still alive and moaned about the conditions of the Kurdish jail where he is being held.

John and Sally Letts said their son has been left to die after being caught while trying to flee the terror capital of Raqqa.

The couple – who claims he never fought for ISIS – have said he has been abandoned by ministers letting him face “vigilante justice”.

They have now turned to the Canadian government to try and rescue their son as he has a dual citizenship.

Jihadi Jack, an Oxford schoolboy, claims he was captured after fleeing from ISIS when he became disillusioned with the group.

JIHADI JACK: Jack Letts fled to Syria while studying for his A-Levels to join ISIS

Jihadi Jack claims he had tried to kill himself because conditions in the Syrian jail are so terrible – blubbing he wanted to tell his parents “I’m sorry”.

He claims to have been tortured and kept in a 6ft 3in solitary confinement cell with no toilet.

The lad also fears he might die as he is denied treatment for a kidney condition which causes him agony due to cysts on the organ.

He also revealed he has found a lump on his left testicle.

Revelations about Jack come after the ISIS "Beatles" group were finally busted when the last two members were captured.

JACK LETTS: The teen was a schoolboy when he converted to Islam

Jack said: “Tell my mum I’m sorry. Tell my dad I’m sorry. Tell them if I ever get out of this place

“I am going to try and be a better person.”

He added: "I tried to kill myself but failed when I was in solitary confinement. I started to go insane”, reports the Mail on Sunday.

John, 55, and Sally, 54, have written a letter to Canadian MPs asking for their help to free Jack.

They wrote: “We feel that our only hope for saving our son's life lies with securing the support of parliamentarians who believe in democracy and the rule of law rather than vigilante justice.

“Jack has stated publicly that, if released, he wants to spend the rest of his life 'bearing witness' against ISIS."

The jihadi reportedly went by the name Abu Mohammed and married a woman with whom he has a son while living in the so-called caliphate.

He converted to Islam while at Cherwell comprehensive school and travelled to Jordan, aged 18, having dropped out of his A- levels.

His family have denied he went to Syria to fight and claim he was motivated by humanitarian reasons.

Jack claims he quit ISIS after witnessing them kill their own supporters, and was jailed three times by the cult.