We are looking in the wrong place for the answers, Nasir Hafezi says. We blame raving ideologues, or passages in the Koran. Authorities try to unmask preachers of hate, set up schemes of informants, surveillance and detection at schools and mosques to identify those in need of correction.

But the "starting point" for terrorism is often not ideology or religion, Hafezi believes. It's human nature. Perhaps even one of its better aspects: the instinct for justice.

Hafezi, a mild, thoughtful, community-minded lawyer from a tiny Manchester firm, has handled many of the recent terrorism cases in north-west England. This year he represented a teenager who pleaded guilty to a minor terrorism offence, the first to face such a charge in England's Youth Court. And he observed the case of another, the 14-year-old from Blackburn who, with just a smartphone and a honed sense of grievance, planned an attack on an Anzac Day parade in Melbourne.

He works out of a pokey office in Manchester's legal district, the walls lined with cardboard boxes marked "category: crime", photocopier humming loudly in the background.

He has a politely wary air - he's been burned by the media before, at one stage he pleads directly "go easy on me". But his conscience is an almost palpable presence in the room, as it was at the sentencing of his client.

This was not a solicitor who just wanted the best "deal" for his client, case closed. He wanted her to be understood. He wanted her to be heard, reading the court a high school essay she wrote on global injustice, to show the intelligence and potential in a teenager whose life had gone down a tragic path.

And there is a defiance, as well. It's not every solicitor who will walk out of the sentencing of a terrorist, and tell the gathered media "we as a society should recognise that some young people want to make the world a better place".

Hafezi is also active in the Muslim community. And he has come to passionately believe that "radicalisation" (he doesn't like the term) is being both misdiagnosed and mistreated.

"The younger you are, the more vulnerable you are to inappropriate messages," he says. "But the younger you are, the more you are searching for what to do, what changes you can make in the world, and how to make that change."

Teenage Muslims hear about world events, in Iraq, Syria and elsewhere, not at first on the "dark web" or from underground Islamic State Twitter networks, but from the mainstream media. They then seek answers.

"It's political rather than religious," Hafezi says. "They start from the point of view: 'how should I respond?'

"Young people want to make a difference – that should be encouraged."

But then they fall into a "vacuum", he says. It's a vacuum created by government policy, intended to shut down "hate preachers" and counter their influence and visibility.

Imams and leaders of Muslim communities are no longer permitted to talk politics, Hafezi says: "What you find in mosques is silence."

'Solution' is part of the problem

The problem, as Hafezi sees it, is the British government's Prevent strategy, established after the 2005 London bombings, then revamped by the coalition government in 2011.

It is about to be pushed even further – under new laws announced this month "radical preachers" will be banned from posting material online, schools will be "protected from entryism by extremists", police and local authorities will have greater powers to close down premises used to "support extremism".

On the face of it, it sounds unarguable. Prime Minister David Cameron said the plan would work because it was "comprehensive" .

"It's no good leaving this simply to the police or the intelligence services. It's no good simply talking about violent extremism. We need to confront all extremism," he said.

But the strategy has met widespread opposition. Greater Manchester chief constable Sir Peter Fahy warned this week: "There is a concern that efforts to control extremist narratives will limit free speech and backfire if we don't get the balance right. The efforts to control extremism and limit protest by those caught by too wide a definition may undermine the very rights and British values you seek to protect".

Hafezi says the problem is what counts as extreme? Fear has gripped the community, he says.

"Individuals are concerned that if they raise issues like world politics or local laws or policies there's a fear they will be described as an extremist, a radical or a terrorist sympathiser."

Even he fears being stigmatised this way, he says, for acting as a lawyer for those accused of terrorist crimes, and for being active in the community.

"The leadership in the community is withdrawing. The government is using its powers to stop events taking place. Universities are threatened with sanctions, charities are threatened with having their funding withdrawn. It's very hard to enter the public space.

"We are all worried about becoming 'preachers of hate'."

Schools are no place either for debate and engagement. Public sector workers, including teachers, have a duty to identify and report any pupil believed to be susceptible or vulnerable to extremism. The students know it.

"Pupils won't engage in conversation," Hafezi says.

So teenagers hungry for explanations, for political discussion, go elsewhere.

They find on Twitter and in social and alternative media an account of events in Iraq, Syria and elsewhere that "appears to be more direct – witness accounts, personal experiences", Hafezi says. It feels genuine, credible.

But in fact it's anything but, Jahangir Mohammed, director of the Centre for Muslim Affairs, says.

"[IS] have got a strategy. They want to recruit people, from all over the world, and they are skilful in propaganda. Their techniques are very clever."

Like all modern teenagers, young Muslims are on the internet in their bedrooms, flocking to dating sites, chatrooms and social media. So that's where IS recruiters go.

"They start chatting and they hook you in," Jahangir says. "There are lots of hooks.

"They can be brilliant – it's all psychological."

Like salesmen, they will "read" the target and find what will clinch the deal. To adults they sell a "lifestyle" – marriage, a job, a free car and a home with a swimming pool recently "liberated" in Syria. To others they sell a life of excitement and acceptance, contrasted with the banality and suspicion of home.

When they find a young person with an interest in theology they exploit that, Jahangir says. He calls it "cowboy ideology", verses plucked out of context from religious texts, transformed into something closer to Baathist violence than anything resembling Islam.

But Jahangir too laments that it is almost impossible to counter these ideas in public.

"Nobody is talking to youngsters," he says. Within the walls of suspicion set up around Muslim community leaders, it is too hard to have a genuine discussion about the meaning of jihad, or the messy politics of Syria.

"The new laws close down venues, ban groups – it's totally counterproductive. Schools are being treated as a surveillance centre. It's creating the very problem you are trying to solve. By looking for that one person [being dangerously radicalised] you have radicalised everybody else. Young people need more breathing space. They want to escape."

It's not just the Muslim community arguing these points.

Engagement the best option

Richard LeBaron, a former US ambassador to Kuwait who has worked at embassies in Tel Aviv, Cairo and London, started an online engagement unit within the US Centre for Strategic Counter-terrorism Communications, a network of US officials who overtly engage extremists on Twitter and other online forums.

Formed by an executive order signed by US President Barack Obama in 2011, the centre aims to "reduce the effectiveness of terrorist propaganda" – initially from al-Qaeda, now IS.

He warns against being carried away by the medium. It's the message that's dangerous.

"Everybody is so impressed with ISIL's social media, their videos, their ability to reach people online – I've always been a little suspicious of this, I think it's borderline racism that we think 'gosh, these Arabs they can actually tweet'," he says.

"They can make videos and have a media arm – big deal. They also have a product they can sell. They can sell Muslims being killed, they can sell Assad's treachery and the horror of what he does to people in Syria.

"It's about attracting people because they are actually doing something. And what a 17-year-old in Birmingham or Chicago or Tanzania wants to know in the world is 'how I can change it?'. If your kids aren't saying 'how can I change the world?' they're not worth having.

"So in the West, we've got to have 'here's how you change the world, not by going and getting killed in Syria by a bunch of crazies. But here are some options'.

"We need to recognise they have a legitimate grievance."

LeBaron says it is incredibly difficult to identify "that guy" who will move from exposure to ISpropaganda to taking action.

And here he deviates, somewhat, from Hafezi and Jahangir. He believes that it is not just about giving young people space to explore political views. It is important to listen to them, as well.

"There will be a thousand ... young boys who are reading exactly the same [extremist material] online who do nothing, who go and play soccer. Trying to sense who is going to be the most vulnerable, who is going to do something is very difficult, very intrusive if you do it through espionage or monitoring.

"It comes down to a lot of responsibility to people right around them. Parents, peers, teachers who can see behaviours and see changes in behaviour."

But, LeBaron says, we must be careful about what behaviour we criticise and what we encourage.

We need to recognise the difference between extremism and the desire to address injustice, wherever it is. "Confusing the two just makes people resentful."

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