The people who used to live where the square now is have been relocated to Xuexin village, a newly-built community of attractive, Tibetan-style houses behind the Potala. Thaje, an old man I was taken to visit, had photographs of Stalin, Lenin, Marx, Engels, Mao, Deng and Jiang in the living room of his new sixroom house. "I used to be a serf working in the summer palace of the Dalai Lama," he said, "Then I had little money. Now I make enough." He sells cigarettes, mineral water and packets of instant noodles through a little window. When I asked him what he thought of the Dalai Lama, his wife interrupted to remark hastily: "We can't say what is good and what is bad. Whoever treats Tibet well is good. Now, Tibet is under the Communist party and that is good." Despite their outward devotion to communism, Thaje and his family maintain a Buddhist prayer room, and the previous day he took part in a circumambulation round the Potala, spinning a prayer wheel with other pilgrims.
The Tibetan secretary of the neighbourhood committee, 28-year-old Chong Da told me how Chinese family planning policy is applied in the community of 600 Tibetans. Couples are restricted to two children, she said. The committee sets quotas and decides when women can conceive. She had a baby two years ago and will have to wait one or two more years before she may conceive again. Any woman who became pregnant outside the permitted time would be "persuaded" to have an abortion, she added, though "nowadays people prefer two or three children rather than big families". When I asked him about this, the vice-mayor later repeated the Beijing line that only Tibetan government officials were limited to two children and that in rural areas "there are no specific restrictions - people can have 10 children if they want." Two kilometres west of the Potala, in the old Tibetan quarter, pilgrims prostrate themselves every day in front of the bustling Jokhang, the most revered religious structure in a nation defined by religion, and the old streets are full of people shopping for sandals, yak hair, snuff, herbs, spices, medicines, hardware, felt hats, cotton cloth for prayer flags, and dozens of other daily necessities, just as they have done for centuries. Here, too, new ideas have intruded. Foreign tourists can send emails to their families from the Barkhor Cafe in the square in front of the Jokhang. It became an Internet cafe two months ago when the owner installed four computer terminals and a poster which read: "Internet Service, email, www-hotmail, Telenet". "Not a single Tibetan has used it because they don't know how to," said the young Chinese woman from Sichuan, who was instructing an American hiker in pigtails on sending an email to Colorado. The service, which costs about £3.50 an hour, is not very private - the terminal I used had several old messages in the `sent' box which could be read by anyone, including the Public Security Bureau.
Tibet is a popular tourist destination for back-packers and used to boast a Holiday Inn: after a dispute over standards last year, the hotel was retitled the Lhasa Hotel. It has an unfortunately-named Hard-Yak Cafe with pictures of James Dean and Clint Eastwood, and provides oxygen masks for visitors who get altitude sickness - headaches, nausea and sleeplessness - in the thin 3,600 metre-high (11,811 feet) atmosphere. But it has international direct dialing and in its shop I made a rare find - a beautiful volume in English and Tibetan on the Potala Palace, just published by the China Tourism Bureau. Despite the cultural and ethnic colonisation of Lhasa, the magnificent Potala, a marvel of Asian architecture, still dominates the city. The lonely young Dalai Lama used to watch the goings-on of his subjects from the roof, through a telescope, before being forced into exile. Heinrich Harrer, author of Seven Years In Tibet and one-time tutor to the Dalai Lama, recalls the Potala as "miserably dark and uncomfortable as a dwelling place". Today it is much the same, a gloomy but enthralling museum of chapels, altars, Buddhas, and religious relics lit by low-voltage neon strips and butter oil lamps which are kept topped up from slabs of yak butter by devout visitors. A tasteless Chinese tea room has been opened in an central area where visitors are informed (in Chinese only) of President Jiang Zemin's advice on "maintaining the solidarity of nationalities and national ethnic cultures". The vast building which once housed the Tibetan government and was home to 175 Tsedrung monks of high standing is today empty but for 65 monks, some of who will surreptitiously ask travellers for pictures of the Dalai Lama. The vice mayor told me that display of the Dalai Lama's pictures is forbidden in monasteries as his "splittist deeds" had compromised his position as a religious leader. Photographs of the Dalai Lama are also prohibited in private homes, said Mr Ping, "but if the common people display such items the government won't punish them - rather, it will try to persuade them" to dispose of the pictures. The respected Tibetan author and teacher Tashi Tsering - a supporter of Chinese rule - has no fewer than seven photographs of the Dalai Lama on his living room wall in Lhasa. "Most people have his picture, they respect him," he told me bluntly. But the pro-Beijing authorities are relentless in their campaign to exclude the Dalai Lama from Tibetan life. Visitors to the Potala can glimpse one room equipped with metal-frame chairs for classes in patriotic education, designed to persuade monks that Tibet was "peacefully reunited with the motherland" when Chinese troops arrived in 1950. Clearly, an awful lot do not accept the official line and remain loyal to the Dalai Lama. The patriotic campaign was launched to counter splittist and counter-revolutionary tendencies among the monks, according to Jagra Losang-dainzin, the deputy director of the Tibet Autonomous Region Committee of Nationality and Religious Affairs. Jagra is a living Buddha, one of 304 alive today who were identified in their infancy by abbots as reincarnations of the deity. But with his dark suit, polo-neck shirt and gold watch, he looks just like the proBeijing bureaucrat he has chosen to become, having opted for secular life and married and fathered three children, forfeiting the right to wear robes. Jagra said there were 46,380 monks and nuns in Tibet - the number is fixed by the government - and 1,787 monastic sites out of a pre-1950 total of 2,000. (Old history books say there were hundreds of thousands of monks and nuns in pre-communist Tibet and 6,000 monasteries, most of which were demolished in the wholesale destruction of Tibet's religious heritage which began after the 1959 uprising against China and continued during the Cultural Revolution.) The Tibet Autonomous Region is taking "concrete measures to protect freedom of belief", Jagra said, and 300 million yuan (£25 million) had been spent restoring places of worship since the mid 1980s. At the same time, some feudal practices were banned. A law had been passed preventing "non-adults" being forced into monastic life - which meant monastic orders could not admit anyone under 18. The huge Drepung monastery outside Lhasa is one of those restored to life. Sitting on a hillside like a walled medieval town, it once was home to 20,000 monks. It now has 660, according to a monk making tapers from cotton wool and splinters in an entrance hall - he said openly, despite the presence of a government official, that "all Buddhists needed a picture of their religious leader".
"Monks and nuns are citizens of China and every citizen has the obligation to love his motherland," the living Buddha insisted when I asked why people who opted for a spiritual life should have to undergo political classes. "If they only concentrate on studying Buddhist scriptures and are not familiar with social conditions outside, it would not be appropriate." He said the patriotic campaign involved five courses: the anti-separatist struggle; socialist democracy and law; ethnic and religion policy; safeguarding the unification of the motherland; and adapting religion to the socialist cause. At the end of the sessions, all monks must pass an examination on these topics. He denied they were obliged to pledge allegiance to the motherland but agreed that some monks - a "limited number, very few" - had "failed" and been forced out of monasteries because of their "counter-revolutionary minds". He also pooh-poohed reports that 200 monks were in prison. "Less than that," he said. The patriotic campaign is far from over and seems about to enter a new and harsher phase. The Tibet Autonomous Region Congress acknowledged last week that "the struggle against separatism is protracted, acute and complicated" and "opposing separatism is the top political task facing us". It resolved to "crack down according to law on criminal elements splitting the motherland" and "strengthen according to law control of monasteries and temples and religious activities".
I left Tibet as I arrived - through Lhasa's Gonggar airport, which is an hour and a half drive outside the city along a wide river valley. Gonggar has only 25 passenger flights a week and most bring in tourists from China. Because of dangerous air-flows in the afternoon, it is only open in the mornings. The lasting impression I took away was of a still-isolated country which is a long way from coming to terms with its role inside Chinese borders.
For China it is still, after almost half a century, a major security problem. As I embarked on the flight to Chengdu, en route to Beijing, two unscheduled flights were coming in - Chinese army troop-transport planes, which disembarked dozens of soldiers on to fleets of army trucks on the runway.