Blasphemy in the UK. Photo: Adrian Dennis/AFP/Getty Images

Among the more than 2,000 European jihadis fighting in Syria and Iraq, approval of the Paris terror attacks was universal and emphatic. “The people in the west learned an important lesson,” tweeted a Dutch fighter, Abu Saeed AlHalabi. “Your government can’t protect you when al-Qaeda puts you on their hit-list.”

A British militant with the nom de guerre Hudheyfa Al Britani warned that Muslims should not express sympathy with any of the 17 people murdered at the satirical magazine Charlie Hebdo, Montrouge or the Parisian kosher supermarket. “Any Muslim who attends the JeSuisCharlie solidarity march in Paris is a murtad [apostate],” he wrote on Twitter. A second Dutch jihadi, Abou Shaheed, urged people to follow the example of Saïd and Chérif Kouachi, the brothers who attacked the French magazine, and to “terrorise the enemies of Allah”. Shaheed also called for strikes against the Danish newspaper Jyllands-Posten (which, like Charlie Hebdo, published cartoons of the Prophet Muhammad) and against the anti-Muslim Dutch politician Geert Wilders.

The three European fighters quoted above are all members of Islamic State (IS), yet the attack against Charlie Hebdo has been linked to al-Qaeda in the Arabian Peninsula (Aqap). There is a necessary backstory here. The two terror groups have been engaged in a fratricidal war ever since IS declared its independence from Ayman al-Zawahiri, the head of al-Qaeda (of which Aqap is a regional division). Leaders of both organisations have frequently condemned each other while their members have fought it out on the ground.

IS has made no official statement about the attack on Charlie Hebdo. But the views of two more of its British fighters offer insight into the thinking of the group’s foot soldiers. Abu Qaqa, originally from Manches­ter, tweeted that what mattered was not who murdered the Char_lie Hebdo cartoonists, only that they had been killed.

Talking to me on Kik, a chat application for smartphones, Omar Hussain, 27, a former Morrisons security guard from High Wycombe, said: “I’m not fussed whether it’s done under the banner of Aqap or Isis. As long as the kafir [infidel] has been killed, that’s what counts. Killing a kafir who insults the Prophet is a praiseworthy deed.”

In this context the importance of avenging perceived insults against the Prophet Muhammad transcends even the most bitter institutional rivalries. That much seems clear from the twin attacks in Paris. When the Kouachi brothers fled to the outskirts of the French capital on 9 January, Amedy Coulibaly stormed a supermarket and killed four Jewish people.

It remains unclear how co-ordinated the two events were, but at the least Coulibaly was acting in support of the Kouachis. While the brothers told staff at Charlie Hebdo that they were acting on behalf of Aqap, Coulibaly separately declared his allegiance to IS in a video statement. Rather than this being a joint attack between the two groups, it is worth noting that Coulibaly was a long-standing friend of both the Kouachi brothers, underscoring the importance in terrorist activity of social bonds over self-identified institutional links.

Coulibaly’s common-law wife, Hayat Boumeddiene, is believed to have travelled in early January to Syria, where foreign fighters often punish those deemed to be insulting Muhammad or dishonouring Islam in other ways. “Today we lashed a guy for cursing God, 80 lashes but if he do [sic] it again a bullet!” as Shaheed, the Dutch militant in Syria, wrote on Twitter shortly before the Kouachis and Coulibaly were killed by French police.

In 2014, a British jihadi who calls himself Mujahid Sayyad, who previously attended Queen Mary, University of London, uploaded a video to Facebook that appeared to show several members of his group torturing a member of the Free Syrian Army. The man is bound in a car tyre and turned over to expose the soles of his feet, which are then beaten with a pole. He protests his innocence throughout but is kicked in the head and hit with the baton so hard that it eventually breaks.

Sayyad explained that the man “swore at Allah”, so “there was no stopping us”. He claims their leader had ordered them to teach the man “a lesson”.

For Hussain, the fighter from High Wycombe, it is not just blasphemers who need to be targeted. Settling scores is equally important. He told me he would urge “all Muslims in the west to follow suit” following the Paris attacks and that it is obligatory “to kill the British soldiers returning from Iraq or Afghanistan”.

This chimes with his previous public statements. Last October, Hussain featured in an IS propaganda video calling on British Muslims to “rise up” and “cause terror in the hearts of infidel communities”.

These are precisely the sentiments that worry Andrew Parker, director general of the Security Service (MI5). In a speech to the Royal United Services Institute in London on 8 January, Parker outlined the tangible and significant threat that Islamist terrorists continue to pose.

Syria is the global crucible of jihad today, the arena from which international attacks are both directed and inspired. The crisis there has almost certainly extended the terrorist threat to our shores for a generation – if not two. That might seem alarmist, but consider the scale. Since October 2013, “There have been more than 20 terrorist plots either directed or provoked by extremist groups in Syria,” Parker says. That is more than one a month over the past 15 months. Prosecutors have secured on average three convictions a month for terrorism-related offences in the UK since 2010. Three terrorist plots have been disrupted in the past few months alone.

And while the terrorist threat is intensifying once again, it is also mutating. Jihadi groups are now favouring less sophisticated attacks than before: these are harder to detect and require fewer participants. The most significant strikes on western soil in recent months – in Canada, France and Australia – have all involved gunmen operating either alone or in small groups.

It is almost impossible to stop such attacks. They do not require much preparation and demand little reconnaissance. Guns are also unnecessary; so the relative difficulty of acquiring them in Britain, compared to some other western countries, is no guarantee of security.

As the brutal murder in 2013 of Drummer Lee Rigby in Woolwich, south-east London, demonstrated, everyday items – knives, a meat cleaver – can be used as instruments of war. Nor was this the first time such an attack was carried out on British soil. Three years earlier, in May 2010, Roshonara Choudhry, a university dropout from New­ham, east London, attempted to kill her local member of parliament, Stephen Timms.

Choudhry stabbed Timms because of his support for the Iraq war. He was fortunate to survive but the symbolic repercussions of the attack reverberated: here was a British MP being targeted because of the way he had voted in the Commons.

This is the mercurial threat with which MI5 and its partners must now contend. There is no shortage of ungoverned spaces abroad where young British men might receive the training they need to orchestrate a successful attack here. Syria and Iraq naturally seem like the most likely origins of such a threat, but one must also consider Yemen, Somalia, Nigeria and parts of the Afghanistan-Pakistan border.

What can we learn from the Paris attacks? To start with, we need to analyse the nature and origin of the jihadis’ beliefs. Much has been written of the supposedly “offensive” and “provocative” nature of the Charlie Hebdo cartoons. “Don’t lampoon the Prophet of Islam,” its detractors seem to suggest, “and you won’t be harmed.” This echoes the argument that led to western disengagement from the Middle East and to our relegation to the position of spectators who can only observe impotently while the region implodes at the hands of robed rogues. “Don’t interfere in the Middle East and the jihadis will leave us alone,” went the conventional wisdom as IS began to overrun large parts of Iraq and Syria. Subsequent events have disproved this.

It is true that Saïd and Chérif Kouachi may have taken offence at the cartoons of Muhammad published by Charlie Hebdo but that is not what inspired their attack. The best indication of what actually motivated them comes from their own words during their murder spree: “We have avenged the Prophet Muhammad.”

That process of vengeance explains what the Kouachi brothers were attempting to do. They were seeking not to register a protest, nor to vent their anger at pictures they believed to be offensive, but to impose on the Parisian cartoonists their understanding of the Islamic punishment for blasphemy. Viewed this way, it was an act in pursuit of utopia – of the “idyllic” Islamist society to which the Kouachis aspired – where blasphemers are punished with death.

The attacks in Paris perfectly capture the Islamist impulse to push against the normative values of European society. We have been here before. More than a decade ago Theo van Gogh was killed in the streets of Amsterdam for producing a film that questioned the status of women in Islam. In 2010, Kurt Westergaard, a cartoonist with Jyllands-Posten who drew the most contested of the Muhammad caricatures, narrowly escaped murder after an axe-wielding intruder burst into his house. Months after that attack failed, the Swedish cartoonist Lars Vilks was assaulted at Uppsala University as he tried to show scenes from a feature film showing Muhammad at a gay bar.

Such reactionary attitudes are not limited to the European mainland but also run deep in many parts of British Muslim life. Almost exactly a year before the Paris attacks, Maajid Nawaz, a prospective parliamentary candidate for the Liberal Democrats and counter-extremism campaigner, tweeted the most innocuous of cartoons depicting Muhammad. The image, from a popular cartoon strip known as Jesus and Mo, featured a stick-figure Jesus saying “Hey” to Muhammad, who replies: “How ya doin?”

By tweeting the image, Nawaz was saying that he did not find it offensive and that “God is greater than to be threatened by it”. God may well have risen above it but his self-appointed British vicegerents certainly did not. Mohammed Shafiq, who leads the Ramadhan Foundation in Manchester, initiated a torrent of abuse against Nawaz. “Tweeting the J&M [Jesus and Mo] cartoons is abysmal,” he declared. “Just appalling.”

An intense campaign of intimidation followed. Petitions and emails directed at the Liberal Democrats urged them to drop Nawaz as a PPC. Shafiq also threatened to “notify all Muslim organisations in the UK of his [Nawaz’s] despicable behaviour and also notify Islamic countries”. Nawaz lost count of the subsequent death threats, although Shafiq has always insisted that he never intended to incite any physical harm against him.

The reference to “notifying” Islamic countries in the context of that episode is particularly important to consider here, not least because both Nawaz and the creator of the Jesus and Mo cartoon strip live in Britain. What concern should it be of any foreign power what free citizens do in their own country?

Blasphemy has long been the concern of foreign despots seeking to project legitimacy. This was memorably highlighted in 1989 when the Iranians issued their fatwa against Salman Rushdie for writing The Satanic Verses, but it was not an isolated incident of religious establishments seeking to silence creative expression.

Laws against blasphemy exist across large parts of the Muslim world, often with draconian punishments for offenders. A report published by the International Humanist and Ethical Union in 2013 found that apostates or blasphemers can receive the death penalty in 13 countries, all of them Muslim: Afghanistan, Iran, Malaysia, the Maldives, Mauritania, Nigeria, Pakistan, Qatar, Saudi Arabia, Somalia, Sudan, the United Arab Emirates and Yemen.

Even while the Paris manhunt was still under way, Saudi Arabia began punishing a liberal blogger, Raif Badawi, with a sentence of 1,000 lashes and ten years’ imprisonment plus a fine of £175,000, supposedly for insulting Islam. Badawi’s wife, Ensaf Haidar, told the Guardian, “The Saudi government is behaving like Daesh [a pejorative Arabic acronym for Islamic State].”

This is where the distinction between our allies – such as the Saudis – and our opponents such as IS breaks down. Both operate a policy of strict liability towards any perceived insult against Islam or the Prophet. They are not the only ones.

For 16 years the Organisation of the Islamic Conference, now the Organisation of Islamic Co-operation (OIC), has repeatedly attempted to pass resolutions at the United Nations prohibiting the “defamation” of religion. It is hard to see how this amounts to anything more than an international anti-blasphemy law.

In Pakistan in 2011, when the then governor of Punjab, Salman Taseer, dared to suggest reform of the blasphemy laws, he was assassinated by his bodyguard Mumtaz Qadri. Perhaps most depressing is the realisation that it was Qadri, not Taseer, who was hailed as a national hero after the incident. “The killer of my father,” Aatish Taseer recalled in an article for the Telegraph, “was showered with rose petals.”

Some British Muslim communities are deeply invested in such cases. At the time of his murder, Taseer had been campaigning on behalf of a Christian woman, Aasia Bibi, who had been accused of blasphemy. The case was very polarising in Pakistan and when the complainant suggested he might not pursue charges against Bibi, it was a British organisation, the Khatm-e-Nubuw­wat Academy (the phrase means “finality of the Prophet”), which convinced him otherwise. Pakistan’s Express Tribune reported that some Khatm-e-Nubuwwat members flew to Pakistan to ensure that Bibi would be “chased through hell” and they helped pay for the prosecution lawyers.

That kind of attitude has persisted for decades. When the original fatwa on Rushdie’s life was issued, almost all the leading British Muslim organisations of the time endorsed the sentiment. Iqbal Sacranie, who later became the leader of the Muslim Council of Britain and was knighted in 2005, said: “Death, perhaps, is a bit too easy for him . . .” In more recent interviews Sacranie has said he has since recanted that view. There is no reason to doubt him but the damage is already done.

In both cases previously mentioned, in Saudi Arabia and Pakistan, religious groups or leaders played a role but the source of persecution was the state. Indeed, it is principally Muslim states that heat the febrile international climate surrounding Islamic attitudes towards apostasy. This is why they have tried to introduce legislation to censure and stifle all forms of debate regarding Islam. Even though those attempts have failed, at home they routinely crush satirists, reformers, dissenters­ and apostates.

So, it comes as little surprise that satirical depictions of the Prophet Muhammad have repeatedly occasioned global convulsions of splenetic fury. In such an atmosphere, who from within the Muslim world could legitimately tell terrorists not to kill the cartoonists of Charlie Hebdo?

Shiraz Maher is a senior fellow at the International Centre for the Study of Radicalisation at King’s College London