Down a glum, dark back alley in Istanbul, I found a sinister sight. In a workshop two stern and bearded men were bent over sheets and patches of very black cloth, their sewing-machines whirring urgently.
I was plainly unwelcome and they objected to the very idea of being photographed. I quickly saw why. They were making dark robes and masks for women to wear. They looked to me as if they longed for the day when every woman in sight was clad in their workmanship.
They knew the women would wear them, because one day, not far off, they would have to. These robes would be, literally, a 'must-have' for the women of Turkey.
Those who think of Turkey as a relaxed holiday destination, or as a Westernised Nato member more or less 'on our side' need to revise their view.
And that very much includes our Prime Minister, David Cameron, who last week joined in the fashionable chorus urging Turkish membership of the European Union. Mr Cameron plainly hasn't been properly briefed.
Leave aside the fact that such a step would allow millions of Turks to live and work in Britain, and give us - as EU members - a common border with Syria and Iraq. Mr Cameron really ought to realise that the new Islamist Turkey he so ignorantly praises is much more interested in making friends with Iran than it is in joining the EU. And it is becoming less free and less democratic by the day.
I would say there is a strong chance that we will soon lose Turkey to the Islamic world, much as we lost Iran to the ayatollahs 30 years ago. And there is not much we can do about it - least of all the daft scheme to include this nation in the EU.
Panic-mongering? Well, perhaps. But I would rather monger a bit of panic now than ignore what I saw.
I will come in a moment to the bizarre alleged plot against the Turkish state, which has swept dozens of government opponents into prison in dawn raids.
But first let us take a stroll round the Istanbul district of Fatih. It is noon, and the rival calls to prayer of two mosques are wavering in the baking, humid air.
Not far away is a gigantic Palestinian flag draped over the side of a building. Nearly opposite, a group of pale, intense men in turbans loiter on a street corner whispering into their mobile phones. Where am I? The flag suggests Gaza. The whispering men bring to mind Peshawar or some other Taliban zone.
Or am I in Saudi Arabia? For round the corner comes a phalanx of veiled women, under the vigilant eyes of a bossy man in a prayer cap. There are several grades of these women. First there are the wholly shrouded, their downcast eyes glimpsed through a slot, imprisoned in shapelessness. Most disturbing for me - because I have been to Iran - are those in chadors exactly like those commanded by the ayatollahs in Tehran. There is something particularly harsh about the inverted triangle through which their pale and sombre faces peer.
With them come the women they call 'Tight-heads' - 'Sikmabash' in Turkish. These are a new feature of Istanbul since I was last here a few years ago, in evidence all over this enormous city.
They are mostly young and often attractive. But they have swathed their heads tightly in voluminous, brightly coloured scarves. Their lower limbs are covered by long dresses or trousers, and over this, in the oppressive heat, they wear thin raincoats. Such outfits are available in a successful chain of shops called Tekbir, which means 'God is great'.
Covering up the female sex is big business here now. The owner of an independent Islamic clothes shop complains to me that trade isn't as good as it used to be because he now faces so much competition. He notes that more and more of his clients are young women, rather than conservative rural grandmas.
The Tight-heads are startlingly similar to their Iranian sisters a few hundred miles to the east, who wear a near-identical uniform. Like them, they look as if they are making a point. But there is one crucial difference. The point they are making is the opposite one. The Iranian women mock the headscarf as they wear it, pushed as far back as possible on the head, revealing as much bleached-blonde, teased hair as the piety police will allow.
Their message is: 'The law can make me wear this, but it cannot make me look as if I want to.' The young Turks, by contrast, are saying: 'This is how I want to look, even if the law says I cannot.' For the scarf is banned by law in many universities and in government offices, and they view this ban as a challenge they must defy.
There is no simpler way of making the point that, while Iran is a secular country with a Muslim government, Turkey is a Muslim country with a secular government.
Or so it was. Now Turkey is in the midst of a revolution. In a fashionable waterfront cafe looking across the Bosphorus towards Asia, I spotted two young women sharing milkshakes - one veiled, the other displaying her curly hair and attired in barely-there T-shirt and jeans. I asked them if they didn't find each other's garb awkward. No, they didn't. The swathed one explained that she had decided, from religious devotion, to wear a scarf aged 15. Now 19, she had to go to university in North Cyprus, because most mainland universities banned the veil.
Her companion said she thought it quite possible that, in a few years, she too would be covered from head to toe. My guess is that she will be - the growing numbers of covered women across the Middle East place pressure on others to do the same.
But these are just symptoms. A deeper change is under way. Deliberately unremarked by Western commentators for some years, Turkey has a fiercely Islamist Prime Minister, Recep Tayyip Erdogan. Even now, Barack Obama, like George W. Bush before him, still bleats about how Turkey should be allowed to join the EU. And establishment commentators, encouraged by liberal Turkish intellectuals, absurdly continue to insist that Erdogan is in some way 'moderate'.
How odd. Back in the Nineties, this supposed moderate was railing that: 'The Muslim world is waiting for Turkey to rise up. We will rise up! With Allah's permission, the rebellion will start.' Erdogan was even imprisoned for quoting a fervent Islamist poem that declared: 'The mosques are our barracks, the domes our helmets, the minarets our bayonets and the faithful our soldiers...'
Now he is Prime Minister, he has not stopped thinking this. He simply knows better than to blurt it out.
Fashionable liberals in the West prefer to worry about the sinister Deep State, or Derin Devlet, which they claim really governs Turkey through a combination of military power and thuggery. And they have a point, though not as much of one as they used to.
Mustafa Kemal Ataturk, the dictatorial-founder of modern Turkey, was almost as ruthless as Stalin, using military and police power in the Twenties to sweep away the fez, the turban and the veil, impose Western script and emancipate women. His inheritors are the Turkish army, who have emerged from their barracks four times since the Second World War to stage a putsch, hang a few politicians and drive the mullahs back into their mosques. Even further out of sight, and based on a Cold War organisation designed to perform acts of resistance in the event of a Soviet takeover, are profoundly secret networks of government agents committed to safeguard Ataturk's secular order.
They have made some unsavoury allies. Their existence gives credence to the genuinely creepy Ergenekon trials, aimed at a misty and possibly non-existent secret network of conspirators. The plotters are supposed to have sought to foment a fifth military coup. Personally, I think it a swirling tub of fantasy. In a brilliant demolition job (Ergenekon: Between Fact And Fiction: Turkey's Ergenekon Investigation), Turkish expert Gareth Jenkins has gone through more than 4,000 pages of indictments. And he accepts some wrongdoing has been uncovered.
But he concludes: 'The majority of the accused...appear to be guilty of nothing more than holding strong secularist and ultranationalist views.'
As the case wears on, Turkey slips decisively towards the more alarming end of the Islamic spectrum. Sudan's sinister president, Omar Hassan al-Bashir, has been an honoured guest - despite being indicted by the International Criminal Court on charges of war crimes and crimes against humanity. Erdogan defended the visit by saying: 'It's not possible for a Muslim to commit genocide.'
Equally welcome has been the unlovely Iranian president, Mahmoud Ahmadinejad, tainted by the repression of democratic protesters and by his simpering Holocaust denial. No wonder he is welcome. Iranian gas heats the homes in Turkey's eastern provinces.
And the real significance of the recent clashes off the Israeli coast was missed in the West. Gaza and its problems were not the point. Turkey's new Islamic ruling class was glad of the pretext to downgrade its alliance with Israel. This link, dating back to Cold War days, got in the way of Erdogan's plans to snuggle up to Syria, Israel's bitterest enemy.
Were Turkey only shifting her foreign policy from West to East, that would be startling enough. Remember Turkey is a long-standing Nato member with a huge American airbase on its territory. Thanks to its position, its religion, its military strength, its language and its former imperial rule over this region, it has a powerful influence in the Middle East and in the new oil and gas states of Central Asia. Remember, too, that Turkey's attitude will be crucial to the future of post-war Iraq, with which it has a border.
But things are changing, and growing darker, at home as well. And this is thanks to the Ergenekon affair. Foes of the Islamist government are arrested in surprise dawn raids. One of those scooped up in the arrest net was a 73-year-old woman, head of an educational charity, in the final stages of cancer. Many of the 200-odd accused have been held for years on vague charges. But their arrests fuel the government's claim that it is threatened by a vast alleged conspiracy to bring it down. This supposedly implicates everyone from army officers to journalists.
Above all, the charges are aimed at the army, the force that has kept the mullahs in check, and incidentally kept the women unveiled, in Turkey for the past 90 years.
The supposed plot has now become so enormous that a special courthouse has been built in the suburbs of Istanbul to handle the hearings.
Ilter Turan, Professor of Political Science at Bilgi University, Istanbul, says: 'Erdogan has authoritarian proclivities. He will take journalists to court if he does not like what they write about him. He scolds them for writing critical things. He asks editors, "Why don't you come and tell us about the problem in private before printing it?" He's a potential autocrat who likes to engage in acts of personal generosity, like an old-fashioned monarch.'
But such personal government cuts in more than one direction. If Erdogan disagrees with members of the public he can treat them harshly too. Prof Turin says: 'A farmer came to him about some grievance and said, "My mother is weeping." Erdogan replied, "Take your mother and get out of here!" '
Under Turkey's proportional representation voting system, Erdogan can - and does - choose all his candidates. Critics and opponents can be easily got rid of. His power is about to increase if he wins a planned constitutional referendum set for September 12. If voters want increased 'human rights' they will also have to increase Erdogan's power to appoint judges and other key officials.
Not everyone agrees with the professor. On the far, Asian side of the Bosphorus, I get a different point of view from Ahmet Altan, a columnist and breaker of stories on the dissident newspaper Taraf (the name translates roughly as Partisan). I have to pass through elaborate security to find his paper's office. Altan is without doubt a brave journalist, who has got into trouble by challenging the orthodoxy of oldfashioned nationalism.
And he believes there is a profound, reactionary plot against Turkish democracy, and that the Deep State is out of control.
'Ergenekon is a most serious conspiracy,' he says. 'Their objective is chaos, to keep the Kurdish war going, to topple the government and keep the way open for a coup d'etat, to keep the army in politics and to keep the civilian government weak.'
He is also icily critical of European snobbery towards his country, saying: 'Europeans are mistaken about Turkey. They tried to keep Turkey always at the door, but did not let Turkey in.'
But, in a blast of worrying prophecy, he mocks the weakness of modern Europe, compared with China and America, and predicts that one day Europe will need the Middle East. This is a curious echo of warnings from European conservatives that a new continent called 'Eurabia' is taking shape around the shores of the Mediterranean, which will in the end mean the Islamisation of northern Europe.
He says nobody can really understand-Turkey until he has seen the new Anatolia, the bustling economic miracle, based on a new Islamic middle class, which is the powerbase of Erdogan's AK (Justice and Development) Party. And he warns me against Westernised Istanbul intellectuals who, he says, will mislead me with scare stories.
Perhaps so. One such intellectual is so nervous about Erdogan's thin skin that he asks me not to name him. Some of his allegations against the government - of corruption and Judophobia - are so alarming that I can only hint at them here.
And he flatly contradicts Ahmet Altan about Ergenekon, saying: 'All the government is trying to do is to humiliate and intimidate the army, and make sure it is powerless to interfere in politics in future. This coup attempt is supposed to have been hatched years ago, and never took place - because it had no support in the army. Among all these dozens of people in the dock there is not one who has the power or the prestige to lead a putsch. They're just nonentities. The documents in the case come from nowhere. '
Even more emphatic is an impressive retired general, Haldun Solmazturk, a quiet professional who certainly can't be dismissed as a Westernised intellectual. He told me: 'Ergenekon is a tool to intimidate democratic opponents. I cannot call Erdogan a democratic leader. He has no interest at all in progressive Turkish democracy.
'They have shown no interest in finding a middle way. Ergenekon is a huge pot into which they throw anybody associated with any kind of opposition - the military, the universities, the media. There are people still in prison after three years, with no convictions. Many friends of mine have been arrested. I have no doubt that the majority of the suspects didn't commit any crime.'
Wasn't the general afraid? No. 'They can't intimidate everybody. I am not afraid of them. That is exactly what they want.'
But he is contemptuous of Western politicians who fail to see the direction Turkey is taking. 'I, and many like me, are angry with those in the United States and Europe who have turned a blind eye and a deaf ear to attacks on democracy here.'
Nobody is sure what will happen next. The constitutional referendum next month will test Erdogan's strength. A general election is likely to follow. The secular opposition, useless for years, has just been reinvigorated by a timely sex scandal.
Deniz Baykal, its leader, has been overthrown after a video emerged of him apparently in bed with his mistress. He has now been replaced by a new more competent leader, Kemal Kilicdaroglu - who is a famous foe of corruption. Opponents of the Islamist takeover see him as their last best hope.
But this has probably come too late. Erdogan remains popular with the new middle class, Muslim, prosperous and numerous, happy to be Middle Eastern.
We in Western Europe have long assumed that the world that was created in 1945 would last for ever. But we have not paid enough attention to the rising new nations to our East, or to the new powers, fat with oil and gas, heedless of the old laws of liberty, which are gathering strength as America weakens.
Now we may have to pay attention. Among the bayonet-like minarets and helmet-like domes of ancient Istanbul an East wind is blowing, which I think will chill us all.