Kundnani appears to want to erase this ideological thread from the equation entirely. If not ideology, then what drives the thousands of Muslim youths from Muslim countries—some of them under the control of sharia—to become terrorists?

Kundnani's paper has been published and promoted by an organisation called Claystone Associates, which says it is an "an independent think tank formed to offer research, analysis and reasoned solutions to foster social cohesion in relation to Muslims in Britain".

How "independent"? One of Claystone's directors is also a main writer for Islam 21C, which says it is the "flagship website of the Muslim Research & Development Foundation (MRDF)." Until March 2014, MRDF's managing director was Haitham Haddad. It is hard not to see Kundnani's paper as part of an attempt to rehabilitate ideological Salafism as mainstream Islam in Britain today.

And Islam finds it hard to reconcile itself to being a minority. As the late Zaki Badawi, founder and principal of the Muslim College in London, said, Islam has an inherent drive for expansion beyond spiritual into politics, society and law: "A proselytising religion cannot stand still. It can either expand or contract. Islam endeavours to expand in Britain."

For the benefit of the wider Muslim community in Britain, there is a pressing need to settle this dispute between the government and Islamists over whether non-violent extremism helps push Muslims into violent extremism. The battle lines have been too fuzzy for too long. They urgently need clarifying to allow an open and honest debate, based on hard evidence.

Following the slaughter over Charlie Hebdo, four British Muslims went on a BBC Panorama documentary that I presented to explain why they believed the government was right—that their non- violent but extreme co-religionists were taking Muslims to the front door of violent extremists who then opened it. Whether they go through that door can also depend on the other factors I have mentioned.

The response was a fusillade of vicious personal insults at these Muslim interviewees. Bad manners again got the better of "Islamic etiquette". Some of this abuse was also irresponsible. Abu Eesa, an imam and lecturer, implied the interviewees were "apostates". In the current febrile climate, it is not fantasy to fear a fanatic might try to impose the death penalty. A poll has suggested that a third of young British Muslims support execution for apostates. Abu Eesa also complained that under the Prevent programme "scholars [presumably like Haitham Haddad and Murtaza Khan] cannot express basic Islamic facts to those willing to better themselves".

That is untrue. There is no law against saying that gender equality is "evil" or that homosexuals are worse than "animals" or that democracy is "filthy" or that apostates should be executed. Nor should there be—and if the government's Counter Terrorism Bill does restrict the expression of such beliefs, that would be like poking a beehive and would be unwise. Yet it's happened because the government believes the Muslim community has shown itself to be incapable or unwilling to put its own house in order.

Where then, does the organisation that claims to most widely represent Islam in Britain stand on the impact of non-violent extremism?

The Muslim Council of Britain's (MCB) secretary-general is a physician, Dr Shuja Shafi. He is reported to have said he has "no idea" why some young people become radicalised. That hasn't stopped the MCB from saying what they don't think causes radicalisation.