On a recent Friday afternoon, Imran Akhtar set up a folding table loaded with drug paraphernalia outside the Birmingham Central Mosque in the English Midlands. Akhtar's wares included a pair of syringes and a baggie containing a brown substance that looked like heroin.

Some 30 feet away, people were showing off more conventional fare, including perfume, hijab and prayer rugs. As worshippers poured out following prayers, Akhtar, a bearded father of three, made his pitch.

"We're here to sort of give out advice and information," Akhtar said as people drifted past, eyeing the table tentatively. "It gives you an understanding of what the products look like."

Ahktar grew up at this mosque and visits more than 30 others in this city, trying to help parents recognize if their kids are using drugs. He also warns them that drug use can make their children more vulnerable to radicalization.

Akhtar, 39, works for Kikit Pathways to Recovery, a non-profit service that works with the U.K. government's Prevent program to tackle substance abuse and stop radicalization.

Earlier this year, London's Metropolitan Police said a terrorist attack in the United Kingdom is not a matter of if, but when. Prevent, which relies on help from everyone from imams to schoolteachers, is designed to minimize the risk that an attack will be perpetrated from within.

Targets for recruitment

This year, Kikit mentored more than 60 people in Birmingham at risk of being radicalized, according Mohammed Ashfaq, Kikit's managing director. Ashfaq recalls counseling an unemployed heroin addict in his late 30s, who said jihadist recruiters preyed on his vulnerability. Ashfaq quoted the man describing the way the recruiters worked him.

"I was being told that all my life this country was against me," the man told Ashfaq. "And I was put on drugs by the system, and furthermore, the system is currently destroying Muslims."

Ashfaq says the recruiters offered the man a solution: become a martyr, all your sins will be forgiven and you will go to heaven.

Ashfaq said Kikit provided the man drug and religious counseling, and today, he's clean and working in a restaurant. Ashfaq says Kikit ran the case by Birmingham's local Prevent leader – but protected the man's identity, because he wasn't considered an immediate threat.

This is one of Prevent's success stories, which rarely make the news because of privacy reasons.

Last year, the government expanded Prevent, requiring teachers to alert authorities if they sensed a student at risk. This is one area where Prevent has run into heavy criticism.

Criticism from Muslim groups

Miqdaad Versi, assistant secretary general of the Muslim Council of Britain, says Prevent unfairly targets Muslims and the government has done a poor job of training teachers. Versi says it's easy for an uninformed teacher to mistake something offensive — like an anti-Semitic joke — for something more sinister.

"I know of an example of a young child who happens to be Muslim who accused a young Jewish child of trying to rule the world," Versi recalled. "That is completely and utterly unacceptable by any standard. But it's not a sign of radicalization. The only reason why it was treated as such was because he happened to be Muslim."

Versi says the kid's case was quickly tossed out.

Earlier this year, members of the National Union of Teachers voted overwhelmingly for the government to scrap Prevent. They complained the program generated suspicion in the classroom while yielding few results.

All of this worries Pinakin Patel, a Prevent coordinator in west London.

"I am noticing nervousness from parents and individuals about Prevent," said Patel during a tour of North Kensington, where the ISIS executioner nicknamed "Jihadi John" grew up.

Patel says Prevent has accomplished a lot. He says his proudest case involved working with a school and police to turn around two girls who were flying to the Middle East to join ISIS in Syria.

Patel says criticisms of the program are exaggerated and what he calls the "anti-Prevent lobby" is scaring people away.

"If local communities and organizations start to believe — I'll be honest — the crap that comes out of the anti-lobby, then I'm worried about that because that will stop safeguarding work from happening," Patel says. "It will stop people from being supported."

Melanie Smith, a researcher with the Institute for Strategic Dialogue, a London think tank that combats extremism, thinks Prevent has done much more good than harm. But because of privacy concerns, Prevent hasn't shared a lot of success stories.

"In a lot of cases, I think it's just communicated badly," Smith says.

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