Prevent. The word has a reassuring ring. Just right for a counter-extremism strategy. But will the strategy prevent acts of Islamist violence on the streets of Britain? On Tuesday the coalition's Prevent strategy – an updated and modified version of the Labour government's strategy of the same name – was published, after a six-month delay. The document represents a triumph for the hawkish neocon faction in the cabinet – the Cameron-Osborne-Gove axis – over a motley collection of doveish Liberal Democrats (Nick Clegg, Chris Huhne) and one-nation Conservatives (Sayeeda Warsi, Dominic Grieve, Ken Clarke).

The strategy is based on the so-called "conveyor belt" theory of radicalisation. Developed inside neocon thinktanks in the US, it contends that individuals start off disillusioned and angry, gradually become more religious and politicised, and then turn to violence and terror.

The prime minister summed it up in his speech on security in Munich in February: "As evidence emerges about … those convicted of terrorist offences, it is clear that many of them were initially influenced by what some have called 'non-violent extremists', and they then took those radical beliefs to the next level by embracing violence."

But this isn't the case. In July 2010, a leaked memo prepared by officials for coalition ministers on the cabinet's home affairs subcommittee concluded that it was wrong "to regard radicalisation in this country as a linear 'conveyor belt' moving from grievance, through radicalisation, to violence … This thesis seems to both misread the radicalisation process and to give undue weight to ideological factors".

Then there is the 2008 study by MI5's behavioural science unit. It emphasised that the several hundred terrorists it analysed "had taken strikingly different journeys to violent extremist activity"; few had followed "a typical pathway to violent extremism".

Marc Sageman, a forensic psychiatrist and former CIA case officer, agrees that the "conveyor belt" theory is flawed. In his 2008 book Leaderless Jihad, based on an analysis of more than 500 terrorist biographies, he argues that radicalisation shows no such linear progression, and that "one cannot simply draw a line, put markers on it, and gauge where people are along this path to see whether they are close to committing atrocities".

But Cameron and his home secretary prefer to heed the advice of the education secretary, Michael Gove, who has no discernible expertise or experience in this field. It was Gove who intervened in recent cabinet discussions to ensure that the Prevent strategy included a crackdown on nonviolent, as well as violent, "extremists".

He also had a hand in Cameron's Munich speech, in which the PM endorsed the neocon view that working with non-violent Islamists "is like turning to a rightwing fascist party to fight a violent white supremacist movement". It is a poor analogy. To compare the British National party with, say, the Muslim Council of Britain, an umbrella group for more than 500 British mosques and community groups, is grossly offensive.

A much needed debate on extremism has been tarnished by smears, innuendo and outright lies from a bevy of pseudo-experts who trade on the fact that the average member of the public cannot distinguish between an alphabet soup of acronymed Muslim groups – MCB, MAB, MAC, IFE, HT, Fosis and the rest. To pretend that the pro-democracy Muslim Council of Britain, whatever its flaws, shares political or religious values with the pro-caliphate Hizb ut-Tahrir or the pro-Taliban Muslims Against Crusades is deliberately disingenuous.

And how do we define extremism or extremist views? In recent years the bar has been raised repeatedly. It is no longer enough to eschew violence or to participate in elections. In his Munich speech the prime minister included "equal rights regardless of race, sex or sexuality" in his list of non-negotiable British values: "to belong here is to believe in these things."

Really? Will the Haredi Jews of Stamford Hill, north London, be held to these same standards of integration and moderation? How about the Conservative party, which backed the homophobic section 28 as recently as the 2001 general election? As for gender equality, this is a prime minister who has just four women in his cabinet – only one more than Hamid Karzai's cabinet in Afghanistan. Is Cameron an extremist?

The new Prevent document continues to muddy the water. It claims, for example, that Fosis – the Federation of Student Islamic Societies – has "not always fully challenged terrorist and extremist ideology within the higher and further education sectors". This is an odd claim to make given that Fosis held a conference on campus extremism as recently as March, where speakers included the Association of Chief Police Officers' Prevent liaison.

But the most egregious aspect of this counter-extremism strategy is how little it has to say about the links between Islamist extremism and foreign policy. The 113-page Prevent document curiously (or should that be conveniently?) contains just four brief references to "foreign policy" – despite a raft of official inquiries, intelligence reports and academic studies in recent years that have explicitly cited it as a key driver of radicalisation.

Iraq merits one passing reference. Yet in July 2010, in her evidence to the Chilcot inquiry, the former head of MI5 Eliza Manningham-Buller said that the invasion of Iraq had radicalised a new generation of young British Muslims: "What Iraq did was produce a fresh impetus to people prepared to engage in terrorism." One of her predecessors, Stella Rimington, has said: "you can't write the war in Iraq out of history. If what we're looking at is groups of disaffected young men born in this country who turn to terrorism, then I think to ignore the effect of the war in Iraq is misleading."

Foreign policy isn't the only catalyst for terrorism, of course. Islamist terrorists are inspired by a hate-filled ideology – a perversion of the great faith of Islam. But holding Islamist or "extremist" beliefs or views – however they are defined – does not inevitably lead to terrorism, as Cameron well knows.

"I very much admire the leadership that you have given to Turkey," Cameron told his counterpart, Recep Tayyip Erdogan, in July last year. But Erdogan is an Islamist; his Justice and Development party is a product of political Islam.

Combating extremism and terrorism requires a nuanced, less confrontational approach. Otherwise Prevent will be nothing more than a word.