The 33-year-old ex-militant, who comes from the ISIS-held city of Fallujah, spoke of becoming disillusioned with jihad after seeing his commanders turn into bloodthirsty, sex-mad savages.
Senior militants are said to take advantage of thousands of young foreign schoolgirls travelling to join the terror group by exploiting a legal loophole allowing them to sign a one-week marriage contract before divorcing them and passing them on another fighter.
But for Hamza, who recently managed to escape his ISIS commanders in Iraq, the final straw was his shock at the terror group's unquenchable thirst for brutal executions and his disgust at the militants' treatment of young Yazidi women who are bought, sold and viciously raped as sex slaves.
Speaking of his time with the terror group, Hamza said that he was paid 400,000 Iraqi dinars a month (equivalent to £231) - but was also rewarded with free food, fuel and access to the internet.