Garvan Walshe is a former National and International Security Policy Adviser to the Conservative Party

Never interrupt the enemy when he’s making a mistake, said Napoleon. Nothing short of violence is as likely to spur the outrage of radicalised young men as heavily armed French police ordering a Muslim woman to take off clothes deemed insufficiently immodest to wear on the beach.

The mayors of Nice and Cannes have been goaded into a culture war without the least clue about the culture they’re attempting to defend. They reflect their voters’ anxiety at what they believe is a strong, determined, Muslim culture, confident in itself, on the rise and capable of extreme violence against people like themselves. Not for them the distinctions between political Islam and the Muslim religion, quietist Tablighis and militant Wahhabis, let alone the gossamer that separates Islamic State, which stones women, chops off thieves’ hands and conducts military operations against civilians, from Saudi Arabia, which stones women, chops off thieves’ hands and conducts military operations against civilians (in Yemen).

They feel their culture is under attack and that the authorities, hemmed in by political correctness, won’t defend them. It’s the same kind of feeling that motivated Leave voters in the referendum and if it isn’t somehow addressed could get Marine Le Pen elected next year.

The authorities are failing because they’ve forgotten that the defining Western value is freedom. We believe that our system of government is superior to that practiced in Iran or Saudi Arabia or by ISIL because we’re supposed to allow people to do what they want as long as they don’t prevent anyone else from doing the same.

This liberty has never sat well with religion. Thorough-going Christianity and Judaism, Hinduism and Buddhism, all try and control women’s behaviour, and all misinterpret the idea of religious tolerance to impose their views on the rest of us. It’s no surprise that thorough-going Islam, generously supported by our allies in Saudi Arabia, should try the same.

Political Islam is most dangerous to freedom not when it mounts a frontal attack on the West in the form of terrorism, but when it claims that the values we profess require us to accommodate its project to impose itself on Muslims who live here, and in the end bring about radical change to our whole society.

The wrong way to meet this challenge is to defend Western values because they are “ours” — to say, in effect, you’ve come to our house so play by our rules. This leads to the indefensible on French beaches. They may have their religious police, telling women to cover up. But now, at last, we have our secular police telling them to take clothes off instead. By descending to this level we give up the freedom that makes liberal civilisation special.

The right way is a good deal harder. There are some women who put on headscarves as as an assertion of identity not unlike like dying one’s hair black and getting tattoos of pentagrams in prominent places. But it isn’t only a phase people grow out of. Nor is it quite right to say that it’s just an assertion of identity, like wearing a cross or Star of David.

A symbolic assertion of identity wouldn’t cause the discomfort and alarm that the growth and increasing severity of Islamic dress codes for women provokes. A few eccentrics wearing weird stuff because they think their religion requires it isn’t enough to perturb a society. But the concept of hijab – Islamically derived rules of modesty for women – does. It’s a concept with Western equivalents (not long ago even piano legs were given petticoats lest they titillated Victorian men) and now, as then, it’s about controlling women and their sexuality.

The doctrine disturbs because it insists that of all the different ways to be a woman in modern society only one is allowed. All that power, self-expression, experimentation, emotional growth and sexual enjoyment that modern society permits women is denied by this doctrine of modesty, which is about so much more than dress: it covers a range of behaviour from physical contact with non-family members to being verbally assertive in public (both, unsurprisingly, frowned upon).

We should find this Victorian doctrine of control, which threatens the progress women have made in the last hundred years, disturbing (as I think we also do when similar doctrines are imposed on ultra-orthodox Jewish women). It co-opts the desire to assert identity into a sexist doctrine that advances itself, shielded by an appeal to religious tolerance. But we need to argue against its content, not coerce people who display its symbols.

There are plenty of forms of Islam compatible with life in Western Europe today: Saudi-inspired sexism is not one of them, any more than the ultramontane Catholicism of De Valera’s Ireland or Franco’s Spain would be. But if you do want to wear a burkini to the beach in searing summer heat, the police should protect your right to do so, not threaten to fine you for the privilege. Anything else betrays the liberty for which the West is supposed to stand.