The “godfather” of the British jihadi movement, who recruited dozens of young men to fight in foreign wars, has said he now regrets opening the way for people to join terror groups such as Islamic State and al-Qaida.

Abu Muntasir, 55, who lives in Suffolk, was one of the first influential propagandists in the UK for a radical Islamist message. Active in the 1980s and 1990s, he helped to radicalise “thousands” of young Muslims, encouraging many of them to travel to fight in wars in Afghanistan, Kashmir, Burma, Bosnia and Chechnya.

Among the first to invite speakers to the UK from abroad who preached violence and hatred to disaffected Muslims, he distributed speeches from hate preachers Ali al-Timimi, now serving a life sentence in the US for inciting terrorism, and the late Anwar al-Awlaki, who was killed in a controversial CIA drone attack in Yemen that also left his children dead.

In a documentary by Emmy-winning film-maker Deeyah Khan to be shown on ITV this week, Muntasir and several former extremists speak of their deep regret at the decisions of hundreds of UK Muslims to travel to join Isis in Syria and Iraq, and of their efforts to educate young people away from the same paths they followed as angry young men.

Muntasir, who is seen sobbing in the film as he recounts the horrors of his own days on battlefields in Bosnia, Afghanistan and Burma, is described as one of the “founding fathers of western jihad” and admitted that he worked to “create the link and clear the paths. I came back [from war] and opened the door and the trickle turned to a flood. I inspired and recruited, I raised funds and bought weapons, not just a one-off but for 15 to 20 years. Why I have never been arrested I don’t know.”

He said it was not until he realised, while fighting in the jungles of Burma with armed resistance groups, that what was going on was not a holy war, but nothing less than the butchery and exploitation of young Muslims, that he turned his back on violence. “If people want to call me a coward, fine – I’m a coward.”

Muntasir, founder and chief executive of Jimas, said it was time for people who supported Islamic extremism to ask why their sons and daughters were being blown up for false ideals in “unwinnable wars”. Hate, he said, is not what Islam or the prophet taught.

“It was a virus with which we infected a generation. Now it has proliferated,” said one of Muntasir’s former followers, Alyas Karmani, now a peace campaigner, youth worker and imam in Bradford. He said the psychology used by Isis to groom youngsters is similar to that which Muntasir used to bring in followers.

“He was a charismatic father figure. It was exciting and there was an energy. I was an activist, never an extremist. For me I always had an inner voice telling me that a lot of this is not right.

“But I was angry. I had a very violent dad. I had a lot of racism. I was angry and frustrated. So we planted this virus. And the kids today have caught it.

“It’s the same attraction then as it is for young people now. A range of factors that is the same for Muslims and non-Muslims. Young people want to change the world, to feel loved and have a sense of belonging, a sense of attachment. That might just be in a foreign field.”

Speaking to the Observer, Karmani said that to tackle the numbers of young people leaving the UK for Syria, Iraq and Libya, it was important that the debate should change to understanding the human elements at play.

“It’s not about ideals – 90% of them never subscribe to the ideals – it’s other factors that are a draw. This is the new rock and roll; jihad is sexy. The kid who was not very good-looking now looks good holding a gun. He can get a bride now, he’s powerful. The Isis gun is as much a penis extension as the stockbroker with his Ferrari.

“There is a fundamental disconnect with our young people. Youth work used to be a brilliant vehicle but that’s all gone in the cuts, so who connects with young people now?”

He said many first- and second-generation immigrants were forced to live double lives. “I do blame the parents. If their kids aren’t able to talk about what’s going on in their lives outside the house, that’s a massive problem.

“If they have to be repressed about sex, about their friendships, who are they going to talk to? It makes them exposed and vulnerable. We have to stop seeing Muslims as ‘other’. They’re not. See them as the same.”

In making the film, Khan, “born in the west to parents from the east” and forced to give up a singing career because of extremists threats to her and her family, said she had been shocked by many attitudes she found in talking to young people across the UK: “I was horrified to find so many people with backgrounds like mine turning to extremism.”

Exposure: Jihad – A British Story will be on ITV at 10.40pm on 15 June