Mosab Hassan Yousef is the eldest son of a founder of the militant Palestinian movement Hamas.
He grew up with privileged access to the inner circle of the Palestinian leadership.
He was captured and tortured by the Israelis but then decided to become a spy for the Israeli secret service Shin Bet. Over ten years he became one of their most valuable intelligence assets.
His life under threat, he embraced Christianity and now lives in America. He tells Zeinab Badawi how he feels about being regarded as a traitor to his family, his people and his faith.
You can watch HARDtalk on Wednesday 12th May on BBC News Channel at 0230, 0430 and 2330 BST and on BBC World News at 0330, 0830, 1530 and 2030 GMT.