"For many years the 14th Dalai Lama and his 'government-in-exile' have been distorting the policy for Tibet followed by the Central Government." The seat-back magazine, "China's Tibet", on the flight from Chengdu to Lhasa, went on to bombard the reader with numbers and statistics: the mileage of new roads built in the Tibet Autonomous Region; the increase in GDP; grain production tonnages; the sums of money spent on new TV and radio broadcast facilities. There was an article about the jail in Lhasa's old town where, before the "liberation" of Tibet, prisoners suffered horrendous tortures, all of which were approved by the Dalai Lama; another showcased the improvement in the lives of Tibetan nomads, who now live in cosy houses instead of their flimsy old tents; a historical feature traced China's rule over Tibet back to antiquity, finding many precedents and justifications for the current occupation. Criticisms of China's policy towards Tibet from "splittist factions" were "obviously lies". I was sure that it wasn't just the gloopy bowl of rice congee I'd had for breakfast that was making me feel slightly nauseous.

I was travelling with an organised tour for the journey through Tibet, since it is virtually impossible to obtain Tibet permits from the Chinese authorities without being part of a group. Starting from Kunming in Yunnan province, we travelled north to Lijiang, then reached Chengdu by a combination of bus and overnight train. We'd heard reports that for most of the previous week flights to Lhasa had been canceled due to dust storms, so we were all apprehensive as we waited in the airport departure lounge. But that day conditions were good, and there were spectacularly clear views of the mountains during the flight. The plane dropped into a valley for the final approach to Gonkar airport, and hills of bare rock towered on either side. I didn't know whether we were really descending, or if the ground was just rising towards the plane as we neared the runway. Clearing through immigration was a surprisingly painless process, and when we emerged into the car park we were met by our Tibetan guide, who presented each of us with the customary white kata scarf. Welcome to Tibet.

We drove from the airport into the city, along the river valley and past clusters of single storey white houses with burnt red-brown hills looming up behind. On the south-facing walls of the houses, patties of yak dung - used for fuel, since firewood is almost non-existent - were stuck up to dry. Prayer flags rose skywards from the roofs and fluttered in the wind. A few birds of prey soared in the thermals. As we neared Lhasa, our bus had to wait in a traffic queue to allow a convoy of Chinese army trucks to pass (eighty two of them - we counted). Our hotel was right in the centre of town, very near to Barkhor Square and the Jokhang temple, one of the holiest pilgrimage sights in Tibet. The streets around the temple serve a dual purpose - for the tourists, they are lined with market stalls selling souvenirs; for Tibetans, they form a kora, or pilgrimage circuit, around the temple. Performing circumambulations of the temple accrues merit for the pilgrim. Some of them measure the length of the circuit with their bodies, prostrating themselves fully on the ground and walking forward one body length after each prostration. The extremely devout (or maybe those with particularly heinous sins to atone for?) do it sideways. The temple draws pilgrims from all over Tibet, and I was fascinated at the faces and the clothes; beautiful weather-beaten faces, carved by the harsh wind and burning sunlight, heavy yak-skin coats and hats, filthy overalls carrying the dirt of thousands of prostrations. I followed the kora, and as I turned the corner back towards Barkhor Square, the Potala Palace came into view, sitting on a hill overlooking the town. I stood there grinning inanely at everything like a village idiot, trying to take it all in; it was all just so... different!

The next morning we explored the inside of the Jokhang temple. As we entered, the bright sunlight of the square was replaced by a murky gloom, the faint light of yak-butter lamps reflecting off the red-ochre walls and pillars. The clockwise route around the inside of the temple forms another kora, and pilgrims were packed in shoulder-to-shoulder, slowly shuffling forwards. No one prostrated themselves on this circuit - there was no room. A low buzzing sound filled the air, murmurings, hundreds of voices reciting mantras, the faint whirr of prayer wheels being spun. People tipped molten yak-butter from their small candles to replenish the temple lamps, or left offerings of a few jiao (very low-denomination banknotes) in the hands of Buddha images. The dark walls were covered with murals of Buddhist deities - peaceful manifestations in meditative postures, or wrathful ones wearing garlands of skulls and shrunken heads, wielding swords and carrying skull-cups brimming with blood, reminders of the transience of life and the inevitability of death. Sometimes the lamp light would flicker onto the faces of these monsters, making their eyes flash. In Buddhist philosophy the fierce deities are the guardians of the dharma, the law - they fight against the demons of ignorance and protect the devout. It was kind of reassuring to think that all these scary monsters were meant to be the good guys. We followed the pilgrims through the upper levels of the temple, and came out onto the roof, where we spent a long time just starting out across the square to the Potala Palace, and trying to convince ourselves that we were actually here.

The Potala was the Dalai Lama's winter residence, and the seat of the Tibetan government before 1959, when the Chinese crushed a Tibetan uprising and the Dalai Lama fled to India. From the outside it is an architectural marvel, but inside it feels ghostly and deserted. The rooms that are open to visitors contain beautiful artworks, murals and incredible three-dimensional mandalas, but there is an emptiness to the place, and the feeling (probably not unfounded) that one is constantly being watched. There are certainly security cameras everywhere, and maybe a few hidden microphones as well. Much less imposing, but more personal and intimate, was the Norbulinka, the summer residence. We walked through the Dalai Lama's reception room, bedroom, bathroom, and his living room containing a big Russian radio set. At the top of the main entrance stairs, a clock is stopped at 9pm, a reminder of the hour at which the Dalai Lama left the Norbulinka in disguise to begin his escape to India on March 17, 1959.

Although it is only a short bus ride out of town, Sera monastery feels remote and isolated. Once, this was one of the biggest monasteries in Tibet with many thousands of monks, but now only a few hundred are left. The Chinese authorities keep strict control of the numbers of monks, viewing them with extreme suspicion. We were here to watch the monks' debating session. In Buddhism, every tenet of the religion is open to rigorous discussion, testing and argument - if a certain point is found to be unsupportable, it can be discarded. Unlike certain other religions, blind acceptance of received wisdom is not encouraged. I doubt that I would have understood many of the debates at Sera even if they were conducted in English, but the entertainment was provided by the way the debates were conducted. It was all very boisterous and very un-monkish. The monks arrange themselves into pairs or small groups, one sitting, the other standing. The way it seems to work is that the standing monk has the task of convincing the sitting monk of the correctness of a certain esoteric point of Buddhist doctrine; he emphasises the "punch-lines" of his argument by clapping his hands together, and when he thinks he's finally reached the big proof or rebuttal that seals the argument, he reels back on one leg, then surges forward at his (seated) opponent in an elaborate kung-fu style movement that leaves him pointing an accusing finger at the guy's head. Touché! Despite first appearances, it's all very good-natured and humorous, and those in the tour group who were waiting for it to degenerate into Monkey-style stick fighting were disappointed.

Towards the end of the debating session, a couple of us got talking to one of the monks who spoke good English. He explained the significance of the handclaps, but unfortunately couldn't enlighten us about what subjects the monks might be discussing. He told us how the number of monks had dropped so drastically under Chinese rule, and about the many restrictions on religious freedom. He seemed to grow in confidence the more he spoke. At last, he reached inside his robe and brought out a small locket, which he opened to reveal a photograph of the present (14th) Dalai Lama - a serious crime in Tibet, where such pictures are outlawed. He said he knew the sort of trouble he could get into, but that he must make at least a small effort to stand up to the Chinese. A shining example of the strength of Tibetan religious devotion in the face of oppression? Or a Chinese agent gaining our confidence in the hope that we would incriminate ourselves and reveal our plans to destabilise the unity of the Motherland? Impossible to tell, of course, but none of us were taking any chances. We moved the conversation on to the subject of the weather.