We have a blasphemy law. No electorate has approved it. No parliament has passed it. No judge supervises its application and no jury determines guilt beyond reasonable doubt. There’s no right of appeal. And the penalty is death. It is enforced not by a police bound by codes of conduct, but by a fear that dare not speak its name; a cowardice so total it lacks the courage to admit it is afraid.

The British are the world’s worst cowards. It is one thing to say you don’t approve of Charlie Hebdo’s cartoons. But the BBC, Channel 4 and many newspapers won’t run any images of Mohammad whatsoever. They would at least have acknowledged censorship if they had announced that they were frightened of attacks on their staff. They would have clung to a remnant of their honour if they had said: “We are not censoring out of respect. We loathe the murderers who enforce their taboos with Kalashnikovs. But we do not want to spend years living in hiding, as Salman Rushdie did. Or be stabbed in the street, as Theo van Goghwas. Or hear an Islamist smash at our door with an axe and cry: “We will get our revenge,” – as Kurt Westergaard did. So we are backing away.”

Admittedly, an honest admission that terror works would shred the pretence that journalists are fearless speakers of truth to power. But it would be a small gesture of solidarity. It would say to everyone, from Pakistani secularists murdered for opposing theocratic savagery, to British parents worried sick that their boys will join Islamic State, that radical Islam is a real fascistic force.

Instead, most journalists have lived a lie for years, as have many in the arts, academia and comedy. We take on the powerful – and ask you to admire our bravery – if, and only if, the powerful are not a paramilitary force that may kill us.

The mass murder of cartoonists and police officers at Charlie Hebdo, and the attacks on Jews, which revive so many foul memories of European fascism, will change our world – almost certainly for the worst. Unless we find the courage to overcome fear, the self-censorship will spread, and not only in the media.

Colleagues who wanted historians at a London museum to talk about the long history of depictions of Muhammad in Islamic art last week were met with panicking press officers trying to shut them up. Historian Tom Holland, who received death threats after he challenged the creation myths of Islam, said: “I cannot think of any other area of history where debate is so nervous.” He hopes that historians will continue to say that the Koran was a manmade creation, but doubts that journalists will be keen to take their work to the public.

This is not a small capitulation. In the 19th century, the textual criticism of German scholars revealed that the supposed word of God in the Bible was a mess of competing stories. It did as much damage to Christianity and Judaism as Darwinism. Anyone hoping to repeat the exercise by taking apart the Koran and the hadiths today will be restrained by the fear that they will end up as dead as satirists who try to do the same with anti-clerical humour.

My friend and comrade Maajid Nawaz was a jihadi before he converted to liberalism and understands the totalitarian mind. He says that people still do not realise that radical Islamists do not just want to impose their taboos at gunpoint. They want to “create a civil war” so that European Muslims accept that they can only live in the caliphate; to encourage the rise of the white far-right so that ordinary coexistence becomes impossible. If they win one demand, as they are winning in Britain, then they will up the tension and move to another.

As soon as you look at demands rather than labels, the wall dividing extremists from the rest begins to crumble. Saudi Arabia is Britain’s trusted partner and ally. It receives vast quantities of armaments and in turn pumps propaganda into British mosques and universities. As Paris looked like a war zone, it flogged the Saudi liberal Raif Badawi forinsulting Islam. At least they did not kill him, you might say. But if the religious courts had found him guilty of apostasy – that is, of taking the adult decision to abandon the religion of his childhood – the sentence would have been death.

European liberals ought to have stopped, as the lash fell on Badawi’s shoulders, and wondered about their queasiness at criticising the religions of the “powerless”and “marginalised”. The Saudi Arabian monarchy is all too powerful, as are the other dictatorships of the Middle East. Power depends on where you stand and who stands below you. The unemployed man with the gun is more powerful than the Parisian journalist. The marginal cleric may have a hard life, but if he sits in a sharia court imposing misogynist rules on British Muslim women he is to be feared.

European liberals might try to be true to their principles and ally with dissidents, liberals, leftists and free thinkers within Muslim communities. They might help ex-Muslims who fear that one day they will be murdered for apostasy. They might reflect that a Muslim man will encounter xenophobia from the right, but they will hear no rigorous criticism at university or other leftist institutions of the sexism, anti-semitism, homophobia and bloodlust of militant religion.

Self-interest ought to be a motivator. Fear of radical Islam is not only driving support for the National Front in France and Ukip here, but providing an excuse for more attacks on civil liberties, including, despite David Cameron’s pious words after Charlie Hebdo, attacks on freedom of speech.

I hope I am wrong, but I cannot see a culture shift on this necessary scale happening. I fear we must look forward to a lying and frightened future.