By noon the field seethed with people and livestock, heat and dust. Buyers squeezed the flesh of sheep, haggled over cows, donkeys and goats. Alongside, the snack stalls were doing a roaring trade. A baker with an ear-splitting yell invited customers to taste his piping hot samsa, small pastry parcels of lamb and onion that he plucked from the domed walls of his tandoor oven. Young men lolled on ironwork benches under a canvas shelter, eating ice cream with a spoon as they watched noisy Kung Fu films on a propped-up television. Everywhere, people were slurping fruit juice or cool jellies in spicy dressings. The crowds milled around, talking and shouting in a melodic, guttural tongue that sounded like Turkish. The air was filled with the punchy scent of cumin from sizzling kebabs.

At seven o'clock on Sunday morning, the market was already coming to life. Bakers were hooking the first batches of nan bread out of tandoor ovens. Snack-sellers were lighting fires under their stoves, setting up cauldrons of soup to boil, and chopping piles of vegetables and hunks of mutton. The rising sun spilled through the poplar trees bordering the field, marking out long fingers of light on the ground. And already the first market-traders were arriving, steering donkey carts laden with produce, or driving flocks of bleeting sheep into the great livestock enclosure. Hungry after an early start, I bought a nan from one of the bakers. The golden, onion-speckled crust yielded to fluffy white dough: it was magnificently tasty.

I had wanted to go to Xinjiang for some time. Although I hadn't completed my research project on China's ethnic minorities, I'd always been attracted by the diverse cultures of the western regions, and their grasslands and deserts -- wide open spaces that offered respite from the crowded intensity of China proper. As a student I had hitchhiked around the Tibetan provinces of Amdo and Kham, but I'd never made it as far as Kashgar. Years later, it wasn't just the thirst for adventure that drew me to Xinjiang. As a food writer, I had a particular desire to explore a region that lay at the culinary crossroads of Asia.

I found it hard to believe that I was still in China. The only reminder was the occasional street or shop sign, with Chinese characters alongside the local, Arabic-based script. Kashgar, the Silk Road town where this famous Sunday market draws trade from far and wide, lies in the desert province of Xinjiang, at the westernmost tip of the country. This vast region occupies a sixth of China's territory, and is home to myriad ethnic groups, including the Turkic Uyghur people, the largest minority, Tajiks, Kazakhs, Kyrgyz, Russians and, increasingly, Han Chinese.

In Xinjiang one still senses this ancient connection between the Chinese and Eurasian worlds. At the market that day, I wandered among the farmers' stalls, where fruits and vegetables were laid out on the ground. The produce itself was a living record of the region's multicultural history. When the Han Dynasty Chinese envoy Zhang Qian passed through this area in the second century BC on his missions from Chang'an to the kingdoms of Central Asia, legend says he returned with new foodstuffs that were to have a lasting impact on Chinese cuisine: grapes, alfalfa, coriander and sesame, all of which are still of vital importance in the Uyghur diet. Still, you see carts of alfalfa and dried grapes in the markets, and the scent of sesame hangs over freshly baked bread.

More than 2000 years ago, trade began along the perilous overland routes between China and the West that later became known as the Silk Road. Camel caravans carried silk and other luxuries out of China, bringing back spices, precious stones and the sacred texts of Buddhism. Kashgar was one of a string of thriving oasis towns that lay on the route from Central Asia to the glittering Tang Dynasty capital Chang'an (at the site of modern Xi'an). It was only after the opening of the sea routes in the late fifteenth century that the region lost its vitality, and many of the towns were reclaimed by the desert sands.

Other foods such as carrots, cucumber and onions also found their way into Xinjiang, and then China, along the desert roads. The names of fruits and vegetables in the Uyghur tongue carry echoes of languages from all over Asia: the Turkic piaz for onions and uzum for grapes, Chinese words for garlic stems and Chinese cabbage, turup like the Persian torobcheh for scarlet radishes. And, alongside the crops that entered this region along the ancient land routes are sold the New World tomatoes, potatoes and chillies that revolutionised the diet here as in so many other countries.

As usual, I was hovering around the food stalls that day, watching the cooks at work and pestering them with questions. The ice-cream vendor presided over a juddering machine that whipped up ice-cream in a copper cauldron surrounded by ice. At the back of the stall, enormous blocks of ice lay out on a table, melting slowly. 'How do you make ice on that scale, in September?' I asked him. 'We cut it from the frozen lakes in winter, and haul it back to Kashgar on a donkey cart,' came the unlikely reply. But it was true, the ice was mud-streaked and threaded with reeds to prove it. 'We can keep it all summer,' he told me, 'wrapped up and stored in underground pits.'

For me, all this was fascinating. In my early twenties, during that long, hot summer when I stayed with a Turkish family in Anatolia, learning a little Turkish and Turkish cookery, I had stood on the brink of Europe, looking east; and here I was, a decade later, on the edge of China, looking back in the direction of Istanbul.

I chose to eat a bowlful of their noodles rather than mine, sitting at a table in the sun with a motley assortment of Uyghur sheep-traders. The boiled pasta was topped with a colourful stew of mutton and vegetables: red and green peppers, garlic stems, onion, tomato and cabbage. I plunged in with my chopsticks. The noodles were fresh and springy in my mouth, utterly delicious.

At another stall, young men in embroidered caps pulled noodle dough into lengths that they swung and looped in the air, stretching it into strands as fine and even as spaghetti. I persuaded them to let me try. It was an impossible task. In my hands, the dough stretched unevenly, the noodles snapped and shrivelled. Again and again I tried. Occasionally I found my rhythm, and the noodles spun out evenly for a moment, but then they disintegrated, collapsing into a jumble on the wooden board. The boys laughed at me.

The cooking of the Uyghur people, too, has echoes of both east and west. Their noodles and dumplings link with the band of pasta-eaters who live across northern China as far as Beijing, and they eat them with chopsticks in the Chinese style. The Kashgar spice stalls sell the familiar aromatics of Chinese cookery -- Sichuan pepper, star anise, Chinese cardamom and fennel -- but they also dispense herbs and flavourings redolent of Persia and Central Asia: saffron, green cardamom, safflower and rose petals. And while the Uyghur drink tea, constantly, like the Chinese, they show their nomadic heritage in their liking for yoghurt and other dairy foods.

The Xinjiang Uyghur Autonomous Region remains an anomaly in the Chinese empire. The Uyghur people have even less in common with the Han Chinese than do the Tibetans: they are Central Asians in almost every sense, part of the great family of Turks that extends from Xinjiang through Uzbekistan and across central Asia, as far as modern Turkey itself. They speak a variant of Turkish and eat kebabs, and their faith is Islam.

For the Chinese, of course, this was always a barbarian land. In the past, they thought civilisation itself ended more than 1000 miles east of Kashgar, at the Jiayuguan fort in Gansu Province, where the last garrison of the Great Wall marked the boundary of the Chinese empire. From the eighteenth century onwards, however, the Manchu Qing state consolidated its grip on this outlying desert region, and a Muslim rebellion against Chinese rule in the 1870s was brutally crushed. In the 1930s, as China fell apart under the stress of warlordism, revolution and foreign invasion, the local people seized their moment and proclaimed a republic, East Turkestan. But it was short-lived. And then in 1949, Mao's victorious communists swept in with their peculiar brand of 'liberation', which actually meant, as it did in Tibet, de facto colonisation.

Coppersmiths beat their gleaming metal into the curves of cooking pots and kettles, while knife merchants lurked amid rows of bejewelled daggers. Shopkeepers sat cross-legged in the doors of dim Aladdin's caves hung with carpets or old porcelain and trinkets. Dark alleys shimmered with multi-coloured Atlas silks. The men wore Muslim skullcaps or fur hats, the women mixed workaday clothes with peacock finery. Some shimmered through the crowded bazaars in glittering ankle-length skirts, their sparkling slippers kicking up dust as they walked.

In recent years, the Chinese state has pursued an aggressive campaign to develop its impoverished western regions. Han Chinese settlers have poured into Xinjiang, lured by economic opportunity, and Chinese white-tiled buildings have sprung up in every county town. The new part of Kashgar looks, by now, like anywhere else in China, with its dull apartment blocks and shopping malls, its karaoke bars and mobile-phone stores. But when I visited, you could still escape into the narrow streets and bazaars of the old Muslim town, and feel that you were in another world.

There was an almost Mediterranean warmth about the Uyghur. The men clasped hands when they greeted each other; people laughed freely and moved sinuously. All this was delightful to me, and such a contrast to the emotionally reserved Chinese. Even better, Xinjiang was the one place in China where a Western woman, tall, with brown hair and green eyes, could disappear into the crowd if she chose to, and walk through a market without attracting attention. Most of the Uyghur had Caucasian features; some of the local people were fair-haired and green eyed. After the relentless scrunity to which I had become accustomed in China, it was a sweet relief to be so inconspicuous.

On many afternoons in Kashgar, I sat on the verandah of a teahouse somewhere behind the Idkah mosque, watching the donkey carts mingle with shoppers in the marketplace below. Ensconced on one of the carpeted platforms, birdcages hanging above me, I ate nan bread and sipped my black tea. Sometimes, one of the old Uyghur men would take a newspaper wrap from his jacket pocket, and offer to tip some of its contents, black pepper, safflowers or mysterious herbs, into my teapot.

As students in the nineties, intent on venturing into forbidden parts of China, my classmates and I had found the mere existence of Xinjiang fantastically useful. Most of us had never been there, but we had all run into Uyghurs in other parts of China, and been told by Chinese people how much we looked like them. We were well aware that in the backwoods of places like Tibet and Gansu, no one would expect in their wildest dreams to run into an actual Westerner. If we concealed our cameras, fancy sunglasses and conspicuously Western clothing, we could easily pass for 'Xinjiang people', with our big noses and strangely accented Chinese.

One day, out in the Xinjiang countryside, somewhere near the Pakistan border, I left the car I had hired and climbed up a hillside in search of a discreet place to pee. I had been in the region for a week or two, and was dressed modestly in cotton clothes. I had a few scarves wrapped loosely around my head and shoulders, to fend off the ferocious late-summer sun. On my way back down the hill, I was surprised to run into a middle-aged Han Chinese tourist with a long-lensed camera. He gave me a kindly and patronising smile. 'Hello, young lady,' he said, 'So what national minority are you?' He clearly thought he'd discovered a member of a semi-forgotten tribe of nomads, and I didn't like to disappoint him. (Perhaps even now I appear in his photo album as a specimen.)

I did, of course, look bizarre by anyone's standards. Not only did I stand out like a sore thumb on that bus full of Chinese peasants, I looked like no one you would ever run into in Xinjiang or anywhere else in China. Nonetheless, as I knew perfectly well, everyone on the bus would dimly remember some middle-school textbook that rambled on about the colourful, singing-and-dancing ethnic minorities of China, with their outlandish styles of dress and quaint social customs. Some of them might even have seen a few of the colourful minorities on TV. And sure enough, as I listened to the muttered conversations around me, I heard the word 'Xinjiang' crop up a few times. No one had the remotest suspicion that I might be an actual foreigner.

I remember once sitting on a shaky old bus somewhere in the bleak Gansu countryside. I knew that the area I was in was closed to foreigners, so I had tucked my hair into a pair of black knickers and swathed my head in a great black scarf, which I imagined gave me a slightly Arabic air. My eyes were concealed behind a pair of crude, wonky Chinese-peasant sunglasses, my backpack was hidden in the kind of white plastic sack that people used for carrying grain, and I was dressed in jeans, a padded jacket and some Chinese army boots. After buying my ticket from the driver, I sat silently at the back of the bus, trying to avoid conversation with my fellow passengers and to be as unobstrusive as possible.

The people of Xinjiang were also useful to the foreign students of Chengdu in other ways. All over China, Uyghur migrants, most of them young men, set up portable grills on busy streetcorners, and offered lamb kebabs, scattered with chilli and cumin, to passers-by. So strong was the association between these people and the scent of kebabs that you had only to catch a whiff of cumin on the air to know there was a Uyghur nearby. But when I lived in Chengdu, a number of these kebab-sellers had a second line of trade, in cannabis resin, so the smell of kebabs became a kind of sensory analogy for the smell of smouldering hash.

Because of the link between the kebab sellers and the hash trade, you could always tell when a police crackdown on drugs was in progress. Suddenly, with no warning, the aroma of sizzling lamb and cumin vanished from the streets, and you couldn't find a kebab anywhere, however hard you looked. But then, slowly, the Uyghurs would re-emerge from the shadows, the good folk of Chengdu would start eating kebabs again, and the foreign students would resume their habit of getting stoned on Saturday nights.

In a Kashgar backstreet, I watched Ähmät and his family at work in their bakery. People said their nan bread was the best in the district, and in ceaseless demand. Ähmät tended the fire, raking the fierce embers in his tandoor oven, which was set into a platform outside a tiny workshop. Inside, his wife and sister rolled the dough into large rounds, and pricked a pattern into it with a gadget made from chicken's quills. They smeared each round with mashed onion and oil, and flipped it, upside-down, on to a padded cushion. Ähmät then thrust the cushion into the oven, and pressed the dough on to its heated wall. Ten minutes later, when he hooked it out, the bread was a ravishing golden brown, patterned elaborately with quill-pricks and morsels of roasted onion.

The nan is the staff of life for Uyghur people; it has an almost sacred significance. It is used in wedding ceremonies, where the imam invites the bride and groom to share a piece of nan dipped in salted water as a sign of their intended fidelity. It is also part of the visible landscape of the region. As you drive through the countryside, through irrigated fields lined with trees, and villages of adobe homes, there are bread-stalls at every turn. Sometimes a sleepy vendor sits behind a stack of half a dozen small nan; sometimes a stall is laden with dozens of flatbreads of different shapes and sizes. There are large nan the size of dinner plates; small nan like bagels with the hole filled in; shiny glazed nan; nan scattered with sesame seeds or onion; greenish nan made from dough mixed with chopped Chinese chives; sweet nan sprinkled with sugar and chopped nuts or seeds. The nan is a bread with many uses. It can serve as an edible platter for kebabs or juicy steamed dumplings; or be used to wrap food for a takeaway. It is eminently portable -- perfect for a long, gruelling trip across the desert.

The Uyghur share their nan-baking technology with the Persians (who probably invented it), Afghans, Uzbeks, northern Indians and Turks, among others, and it has ancient roots in the region. The museum in the regional capital, Ürümchi, displays fragments of an actual nan from the eighth century, which looks very like those baked in Kashgar today. The Uyghur still treat their everyday bread with reverence. They never throw it away: even stale bread can be resurrected by a dipping in tea. One afternoon, as I walked through an avenue of poplars on the outskirts of Kashgar, a very old lady came up to me and clasped my hands in greeting. Then she rummaged in her pockets until she found a small piece of nan, which she pressed on me as a gift. I still have it in my flat in London.

Soon after my arrival in Xinjiang, I followed my usual practice and went to a bookshop, where I searched for material about the local cuisine. There were the recipe books I'd expected, and one or two volumes about food tradition, but it was a grainy colour photograph in a book on local customs that really caught my eye. It depicted a group of local dignitaries in traditional Uyghur costume standing around an entire roasted camel! On my way to Kashgar, in the nightmarket of the regional capital, Ürümchi, I had seen whole roasted sheep with curly horns, fresh from the tandoor oven, ready to be carved. But a camel? It was enormous! Had they built a special oven?

Of course I spent the rest of the trip asking everyone I met if they knew where I could find a roasted camel. Most of them looked at me as if I was mad. No one had ever heard of such a thing. Although you see camels grazing in the foothills of the Pamirs, to the south of Kashgar, the ubiquitous meat of Xinjiang is the fat-tailed sheep, also prized by the Iranians and other Central Asians. Outside every kebab shop and butcher's stall in the region, sheep carcasses hang, their football-sized lumps of tail-fat obscenely exposed. The fat itself is a delicacy, marvellously aromatic, which is why it is always threaded on to kebab skewers alongside the chunks of lean meat. Whole sheep are slaughtered and cooked for the major Muslim festivals.

I never did find a roasted camel. But one day when I was wandering through the Sunday market in southern Khotan, I almost tripped up on a camel's head, lying in the dust beneath a butcher's stall. Its feet were standing up nearby, like a pair of riding boots in an English country house. Above, amid the bulbous chunks of sheep's tail-fat and the strips of fatty mutton, hung tranches of a darker meat. The butcher told me it was indeed the flesh of the camel, so I bought some, and took it to a nearby kebab stall to be cooked. I retired to a teahouse nearby, and a few minutes later a Uyghur boy made his way through the crowd, bearing my steaming camel kebabs on a nan bread platter. It was good meat, rich and flavourful, and more tender than I had expected.

We hurried past this sad sight and dived into what was left of the Uyghur citadel. It was more like Marrakech than Beijing, with its a maze of blank, adobe-walled alleys, their wooden doorways opening into cool courtyards alive with vines and fruit trees. The scents of rice and mutton mingled around the entrance to the bridegroom's house, where a few men were preparing food in an ad hoc kitchen. A vast wok was filled with the essential wedding food, polo, a rich pilaf made with pearly rice, chunks of mutton and strips of yellow carrot; in another wok simmered a hot-and-sour vegetable stew.

We met at the teahouse the following day, and soon he was leading me towards the old city. We passed the great square outside the Idkah Mosque where the Han Chinese were wreaking their usual architectural carnage. The lovely old Uyghur houses at the side of the square had recently been demolished, and those behind them hung in ruins, their courtyard gardens and wedding-cake plasterwork rudely exposed. The square itself was now fronted by tiled, concrete buildings, Chinese monstrosities covered in a thin veneer of Islamoiserie.

There were other fortuitous encounters on that trip. Sitting in a Kashgar teahouse one day, eating fresh figs, I fell into conversation with Memet Imin, a lively man in his fifties with a charming manner and sparkling eyes. He told me he played in a troupe of musicians who performed at Uyghur weddings. 'There's one tomorrow, come with me,' he said. So I did.

As the musicians played on in the bridegroom's house, a young girl led me through the lanes to the home of the bride. Surrounded by her girlfriends, she was posing for photographs in a white, Western-style wedding dress, her hands patterned in henna, her hair glittered. In the next room, the older women of the family sat around a tablecloth on the floor, feasting. They helped themselves to deep-fried pastries served with sweetened qaymak cream; almonds, sultanas and dried apricots; samsa parcels of mutton, sponge cakes and dough twists; watermelon slices; and some of the literally hundreds of nan breads that were piled up in towers all over the cloth.

On an upstairs verandah, Memet Imin and his band set up their instruments and began to sing and play, filling the air with rousing, passionate music. Little children ran up and down the stairs, and soon a girl brought me a bowl of polo, to eat with my fingers in the traditional way. 'It's very heavy and rich,' warned Memet Imin as he sipped his tea between songs, 'so you should never eat it in the evening, or you won't sleep soundly.'

Amid the merriment of the wedding, I couldn't help thinking of those ruined houses by the Idkah square. Would there be anything left of the old Uyghur town the next time I visited, I wondered? There were no Chinese guests at the wedding, of course: there is little social intercourse between the Uyghur and the Han. Many Chinese people dismiss the Uyghur as luo hou, 'backward', that most damning of Chinese adjectives. 'Filthy as hell,' said one Chinese man who gave me a lift in his car, of the Uyghur, 'They don't know anything about hygiene.' Like most Han Chinese, he saw his people as a force for civilisation, bringing modernity to the benighted natives of the western regions.

As a 'barbarian' visitor to China proper, I am occasionally affected by these echoes of the age-old Chinese racial superiority complex, for example in the hints that Westerners are sexually decadent and somehow unclean. Yet this is so often mixed with such toadying because of the relative wealth of my home nation that it's never a disadvantage. But in Xinjiang, I saw what it was like to be a poor 'barbarian', without the weird kudos of an early industrial revolution and the victorious opium wars, without the glamour-by-association of the American Dream. In Xinjiang and Tibet, I witnessed the spectacle of 'Great Han Chauvanism', unleashed on people for whom I felt an instinctive sympathy.

It's strange for me to hear myself saying such things. I've devoted years of my life to China, and I love the country in so many ways. For more than a decade I've been arguing its case. Yet give me a week or more in Xinjiang or Tibet and I see its uglier side. Unlike many of my compatriots, I've never thought of Chinese popular attitudes to Xinjiang and Tibet as malicious. Most Chinese people, after all, have little access to objective information about either place, and have had no social contact with either Uyghurs or Tibetans. Even Chinese policy-makers, I suspect, consider the demolition of old Kashgar to be an improvement, and wonder why anybody minds. I doubt that Chinese chauvanism in Xinjiang is any worse than racism in Europe or the colonialism of my own ancestors. But it's painful to see.

It wouldn't be so bad if this was Tang Dynasty China, a shot-silk, jewelled, perfumed, star-spangled civilisation, the world's legend. But this is early twenty-first-century China, and the 'civilisation' it bestows on its colonies is often a tacky, off-the-peg outfit of wide roads, sterile concrete high-rises, karaoke bars and brothels. Chinese modernity is bad enough in a Chinese city like Chengdu. In Kashgar it is an outrage.

'Yes, yes,' I said, trying to quiet him, knowing that this kind of talk could lead him into serious trouble, but he wouldn't stop. I left the shop.

'Blah blah blah East Turkestan,' (he mimed a razor blade, slitting his throat), 'Blah blah blah blah East Turkestan' (slash). The door of the shop was open and he was almost shouting.

In the nineties, anti-Chinese sentiment in Xinjiang erupted into riots, bombings, and the assassination of Chinese officials. Many Han Chinese people were afraid to travel to the region. But the flood of Han immigrants that has come in the wake of the economic reforms and a brutal crackdown on dissent have stifled most resistance. People are afraid, on the whole, to talk of political matters.

The Uyghur, of course, burn with resentment against the Chinese. It's dangerous for them to express this openly, but in every private situation, the anger and bitterness flood out. Once I was exploring a biscuit shop, marvelling at the similiarities between the chrysanthemum-shaped pastries within its glass cabinets and the well-preserved eighth-century pastries on display in the Ürümchi museum, when the owner started jabbering at me in Uyghur. I could understand only the two forbidden English words that he said, again and again, referring to the fragile independence movement and the failed Uyghur republic of 1933.

One afternoon a young middle-school teacher, Ali, and his wife invited me for tea at his parents' house. We knelt around a large, low table covered in the nibbles and sweetmeats known as gezäklär. There was nan bread, with sugary preserves made from local apricots and shredded carrot; deep-fried dough twists dredged in sugar; crisp, flaky pancakes the texture of pappadoms; all kinds of sweet biscuits cut into ornamental shapes; and a silver tray of dishes filled with tiny almonds, dried jujubes, sultanas and paper-wrapped sweets. We chatted happily about the life and customs of the Uyghur and the British. But then I asked an innocent question about family size, a sensitive issue in China's minority regions, and Ali thought I was straying into political matters. He froze instantly, and the atmosphere did not recover.

Later that evening, as I wandered with my camera among the pool tables and snack stalls of the Kashgar nightmarket, I was shadowed by a secret policeman, who spoke both Uyghur and English. 'Hello, pleased to meet you,' he said with feigned warmth (his eyes hard, unsmiling), before interrogating me about my travel plans. 'Where have you come from, where are you staying, where are you going, are you working for a newspaper…?' I was deliberately vague in all my replies.

He trailed me for an hour. Infuriated, I took my revenge by using him as a free translator whenever a stall-holder did not speak Chinese. 'Please can you ask this man what exactly is in his dumplings?' I asked him. 'Is it sesame seeds or peanuts?' The spook was irritated, but as he was pretending to be my best friend he had little alternative but to oblige. 'How many spices are in this pigeon stew? And what kind of flour does she use in these fritters?' I went on and on and on, giving him none of the information that he wanted but filling my notebook with recipes. It was deeply satisfying. Eventually he gave up, and melted back into the crowd.

I wasn't followed by the police again, but I did become more sensitive to signs of ethnic tension. And I began to notice how often the Uyghurs' loathing of the Han Chinese coalesced around the matter of pork.

For the Chinese, of course, pork is the staple meat. They eat it on its own or stir-fried with vegetables, they wrap it into dumplings, they use its bones for stock and its fat to flavour almost everything they eat. When the Chinese say 'meat', they mean 'pork' unless otherwise specified. To the Uyghur, as Muslims, the mere idea of eating pork is abhorrent. One taxi driver, cocooned with me in the privacy of his cab, assured me that 'if a true Muslim eats pork, his skin will erupt into blood-spouting boils that can be fatal'. Others spat out that old adage about the Chinese 'eating everything' with expressions of visceral disgust.

Although the Chinese authorities in no way condone such crass behaviour, many Uyghurs feel the government does not try hard enough to protect their feelings. 'In the eighties, there were more sensitive policies on ethnic minorities,' a teacher told me, 'and Han Chinese had to be discreet about their consumption of pork. It was actually illegal to display it in shops or markets, and anyway they would not have dared to flaunt it, because they knew they would be beaten up or knifed immediately. But now the Chinese have tightened their control of the region, and they are no longer afraid of us. They don't care anymore what we think.'

Han Chinese have occasionally used the pork taboo in ways designed to inflame Muslim sensibilities. During the Cultural Revolution, Chinese Muslims were reportedly forced to eat pork and to drink water from wells contaminated by pigs. More recently, in the early nineties, a spate of offensive publications showing Muslims with pigs or pork triggered street protests in four Chinese provinces. Violent clashes between Muslims and Han Chinese in 2000 were sparked off by the hanging of a pig's head outside a mosque.

The Muslim taboo on pork reinforces strong social divisions between Uyghur and Han. Most Uyghurs won't patronise Chinese restaurants, even those that claim to serve food prepared in accordance with Muslim dietary laws. 'You can't trust the Chinese not to use any pork products, whatever they say,' a Uyghur shopkeeper told me. As for the Han Chinese, they tend to see Uyghur restaurants as dirty. And so the two ethnic groups dine separately, and don't talk to each other.

Revulsion at the pork-eating of the Han Chinese is the focus for general anxieties about cultural assimilation and contamination. A few years ago, a rumour that pigs had trampled all over Chinese black tealeaves earmarked for sale in Xinjiang spread like wildfire. It was widely believed that this had been done as a deliberate affront to Uyghur sensibilities, and moreover that the Uyghur chairman of the Xinjiang Uyghur Autonomous Region had published a notice in a newspaper warning Muslims not to drink Chinese tea. 'So everyone stopped buying tea produced in inland China,' one young Uyghur told me, 'and now we buy Indian tea instead.'

As the days drifted by, I found myself developing an unexpected aversion to pork. Perhaps it was all those taxi-drivers, ranting about the omnivorous Chinese, filling my head with visions of pustules and sickness, but I couldn't bring myself to go into Han Chinese restaurants. They started to acquire the dangerous aura of the early English Chinatowns: dark, mysterious, risky places, where you might end up drugged or abducted. Chinese butchers' shops reeked of rapacious carnivorousness, perhaps even cannibalism (those Chinese eat anything). If I ate pork myself, would the Uyghur be able to sense it, just as the Chinese say they can sniff out a dairy-eater in a crowd, from the smell of her sweat?

So I stopped eating pork. Except for once, in Khotan, on the Southern Silk Road. Magnificent though the Uyghur traditional foods were -- those delightful noodles, rich polos, crisp nans and spicy kebabs -- after a few weeks they were becoming a little repetitive for a European barbarian nurtured on the 'hundred dishes, hundred flavours' variety of Sichuanese cuisine. Like most travellers to Xinjiang and Tibet, I had found myself starting to dislike the Chinese, but I was still fantasising about their food. So one night I stole into an upmarket Chinese restaurant in the new part of Khotan. The food was stupendously good: the roast pork, the stir-fried duck, the sizzling chives… It was clearly a place for serious Chinese gourmets, aimed at wealthy jade dealers and local officials. Guiltily, I had to admit that it was the finest meal of the trip. But it left a bad taste in my conscience, a kind of rancid, oily shame.

While I watched, Qurban filled the bags with a pale starchy liquid. As the liquid sloshed through the windpipes, the lungs themselves hissed gently and began to expand. They blew up extravagantly as Qurban filled them with almost unbelievable amounts of liquid. After the lungs had quadrupled in size and looked fit to burst, he bound the windpipes tightly with pieces of cloth. Then, one at a time, he lifted the immense, bulging sacs, hauled them across the yard, staggering under their weight, and hurled them into a vast wokful of simmering water on a brick stove by the gateway.

The Uyghur may not be as omnivorous as the Han Chinese, but some of their traditional foodstuffs are just as imaginative. In a courtyard in one of Kashgar's Uyghur districts, a street vendor named Qurban and his wife laboured over a favourite local street snack: sheep's lung, and sheep-intestine sausages. The scene in their outhouse on the morning I visited resembled a surrealist installation. Two pairs of sheep's lungs, gleaming in the bright sunlight which shone in from the courtyard outside, lay on the ground, their obscene, glistening windpipes attached to the wooden nozzles of dangling cloth bags.

The texture of this delicacy is hard to describe. The pale lungs are smooth as custard, floury as a white sauce, chubby as a cheesecake. In fact, with a little added sugar you might imagine you were eating an English pudding, if it wasn't for the odd tube poking out…

Later, down by the market in a Kashgar backstreet, I tasted the strange fruits of Qurban's labours. On his stall, the great ivory lobes of boiled lung were steaming away, topped with the rice-stuffed intestines made by his wife the same afternoon. He lopped off a few chunks of lung and a few slices of sausage and piled them up in a china bowl, drizzling over a good ladleful of stock. A gaggle of hungry customers were seated at benches around his stall, tucking in.

In late summer and autumn, the bazaars of Kashgar are piled high with fruit. Men crouch over baskets of ripe, juicy green figs cradled in their fragrant leaves, or pull barrows filled with watermelons, pears, or mottled brown-and-green jujubes. There are dried fruits too, as there are all year round: dark, treacly apricots from the Kashgar area, green sultanas from the vines of Turpan, and melons from Qumul in the northeast. But while the region is famous for its fruit in general, it is the pomegranate that has the strongest resonance in Kashgar. In the shady carpet shops around the Idkah mosque, it appears as a motif, woven into the intricate patterning of the local rugs. And in the orchards, large, exotically beautiful pomegranates hang amid dark leaves, their skins glowing yellow, orange and ruby-red.

Both of them, they told me, were traders, running companies that were flourishing with the resurgence of economic ties between China and Central Asia. One of the men, Ismail, was keen to inform me about the nutritional benefits of the Uyghur diet. 'The onions we grow here are very pungent,' he said, 'so they counteract the fattiness of the mutton, and keep the blood pressure low.' The other, Husseyn, explained how the climate of the Kashgar oasis, with its cold nights and scorching days, brought forth the sweetest fruits. We broke open the pomegranates and devoured their sweet, dark juices, warmed by the late summer sun.

It was late afternoon, and two Uyghur businessmen had invited me to join them on their carpeted platform under the pear trees. The teahouse garden was dappled with sun. They sat on either side of a low table, propped up by cushions covered in brightly coloured, shot-gold brocade. There were teabowls on the white tablecloth, and a waitress brought platters of grilled lamb chops, sliced melon and pomegranates. The men were in an easy, expansive mood.

After a while, to my surprise, their conversation drifted into sensitive political matters. 'We Uyghurs are basically the same as the Uzbeks and Turks,' said Ismail. 'We were a great people once, under the Ottoman Empire, but it all ended with the First World War. The problem with the Uyghur is that they are too simple and pure, too trusting. They are easily abused, and now they are angry.' He went on in the same vein.

A slight breeze stirred in the trees; birds twittered in their branches. No one could hear us, but I still felt uneasy on their behalf. Perhaps they felt protected by their wealth and powerful connections, yet I couldn't help thinking of Rebiya Kadeer, the prominent female Uyghur entrepreneur and philanthropist, who was once held up by the Chinese authorities as a role model for the country's Muslims. In 1999, the political winds changed and she was detained for 'endangering state security' because she had sent some newspaper clippings to her husband abroad. She was imprisoned for six years before she was allowed to go into exile in the United States.

But Ismail was still speaking freely. 'The Han Chinese, they are a greedy race. Look at them, with their Kitchen God, and their shrines to the God of Wealth. They are a greedy race. I ask you, what kind of people worship food and money?'