"I was primed because of this racism to already feel that I didn't belong in my own society. I felt that there was something different about me. And it was at that phase, at that stage of my life, that I came across a young medical student," he explained.
The medical student was a recruiter for the group Hizb ut-Tahrir, or HT, which has supporters around the world, from Indonesia to England. Unlike al Qaeda, it does not advocate the use of terrorism, but it is fervently anti-Western and deeply committed to the narrative. When HT recruiters worked on Nawaz, they played on his sense of alienation.
"They broke you down so that you were no longer British. You, a person who had had no religion, became a Muslim," Stahl remarked.
"Yeah. Along came these Islamist activists and said, 'You're being targeted because you're Muslim and non-Muslims hate Islam.' When the skinheads who attacked me didn't have a clue I was a Muslim. They were looking at the color of my skin," Nawaz replied.
"As an angry, young, naive 15, 16-year-old," Nawaz said he bought the argument.
"And I became suddenly not just a Muslim in faith. I became a Muslim in politics. Somebody whose politics were pre-defined by one interpretation of Islam," he added.
Asked what his job was once he joined up, Nawaz said, "To recruit as many people as possible to this group, and spread this narrative far and wide."
After working in England for five years, he was sent abroad to spread the narrative to Pakistan and then to Denmark. When he went to Egypt in 2001, he was arrested in a post-9/11 crackdown on Islamic radicals. It was the beginning of his journey back from extremism, a journey that began in the dungeons of Cairo's state security headquarters.
"Everyone was given numbers. My number was 42. And then what they did, is they started with number one. Called number one into their interrogation cell. And the rest of the hundreds of people that were there would have to listen to number one scream as he was being electrocuted. Then, they would call number two. And everyone had to hear number two scream and get electrocuted. They'd call number three. And they'd go up the numbers one by one. So, you can imagine…I was 42," Nawaz remembered.
"I'd have to listen to 41 people…being tortured," he said.
Asked what he meant by "electrocuted," Nawaz said, "Electricity was applied to their genitalia and their teeth."
During his trial, Nawaz remained defiant. He would walk in and out of court shouting out radical slogans. After he was convicted and sentenced to prison for five years, he was locked up with the assassins of Anwar Sadat and leaders of the Muslim Brotherhood.
"Boy, if you weren't radicalized up until then, you certainly would've been then," Stahl remarked.
"Well, the interesting thing with these guys is that, in the 20 or so years since they've been imprisoned, they'd gone through a process where they had abandoned their jihadist views," he said.
"They did?" Stahl asked.
"Yeah. And my initial reaction was, 'Oh, my God, you've sold out.' And so, I approached them with an idea to try and actually convince them they were wrong," Nawaz said.
Nawaz believed he could "re re-convert" them. "And what ended up happening was through the discussion process, I began doubting the strength of my own convictions," he explained.
They were able to persuade him that today's radical ideology is closer to fascism than true Islam. So after four years in prison, he returned to England in 2006 and soon left HT.
Asked how difficult it was to break away like that, Nawaz said it was "traumatic."
"Because all my friends, friendship circle, my family at the time, my wife was also a member of HT," he explained.
According to Nawaz, his marriage fell apart; they're no longer together.
He decided he wanted to make amends for the 13 years he had spent as a radical, so now he devotes himself to rebutting the very narrative he once passionately promoted.
"Frankly, Lesley, I think it's 'the' key factor in solving the problem we're experiencing in the world at the moment," he said. "Countering the narrative is the core of the solution, making this narrative as unfashionable as Communism has become today."