"I've never really thought about it," Mr Jin added after serving green tea to guests at his office just a few blocks from the Forbidden City. "The ruler should be chosen by the people. Hereditary succession is not good at all." Mr Jin's forbears led the Manchu, a warlike people from what is now China's north-east corner, to seize power in Beijing in 1644. But their dynasty, Sinified and known as the Qing, became enfeebled and racked by intrigue, falling to the republican revolution in 1911.

The story of Pu Yi, who eventually died of cancer while under relentless criticism from Red Guards in 1967, is well known from films and books. What happened to some of the other prominent Manchu royals is now coming out. The catalyst is an exhibition opening at Britain's Oxford University next month of the early paintings by Prince Pu Quan, a noted artist of the traditional Chinese style who was a second cousin of Pu Yi and his brother Pu Ren, Jin's father. Born in 1913, Pu Quan became a professor in the art school of the United States-funded Furen Catholic University in Beijing during the 1930s. One of his pupils was a young British-Indian woman, Katie Talati, whose father managed hotels in China.

Interned for three years by the Japanese, Ms Talati met Pu Quan on her release in 1945 as China plunged deeper into civil war. She left China in 1948 with her mother and sister, before the Communist takeover, farewelling Pu Quan at the dockside in Tianjin and carrying her family's extensive collection of his paintings in her baggage.

Growing up in Beijing and Pu Quan's tutelage helped Ms Talati find a new role. "It gave her Chinese eyes with which to look at the world around her," said Maria Jaschok, a China scholar at Oxford and close friend. Ms Talati was enlisted by the Foreign Office, tutoring generations of diplomats and analysts to speak Chinese and understand the thinking behind the new "bamboo curtain" of Communist China. Pu Quan was lost to the outside world. "I didn't dare try to get in touch," Ms Talati, now 82, said in a telephone interview. "For years I didn't know if he was alive or not, or what had happened to him. It was only in the 1980s that I managed to trace him and his family and make contact." But Pu Quan died in 1991, aged 78, before they could meet. What had happened is related by two of Pu Quan's daughters, who will travel to Britain for the exhibition of the Talati collection, opening at the Ashmolean Museum in Oxford on December 10.

Pu Quan and his elder brother, Pu Xuezai, also a distinguished painter and calligrapher, set up their own little studio, churning out portraits of Mao Zedong for sale to factories and government offices. "Even though he was a traditional Chinese painter, my father knew a lot about Western painting, which helped a lot with this propaganda-style work," said Pu Wenjia, 66. When Mao unleashed the Red Guards to destroy right-wing threats to his power in 1966, the imperial remnants were included in the "Four Olds" targeted as reactionary forces. Young guards ransacked older brother Pu Xuezai's house and ordered him to report for "self-criticism".

Aged 72, Pu Xuezai left home that night with five yuan and coupons for five kilograms of food in his pocket. Thinking at first he might be secretly under the protection of Zhou Enlai, the Mao-era premier who sheltered some intellectuals from the Cultural Revolution, the family lost hope as he failed to re-emerge with the fading of the persecution. His fate is still unknown. Pu Quan also suffered Red Guard pressure, developing a psychiatric illness, hallucinating, and seeing writing in commonplace things. "When he saw a picture of his grandfather, it would say, 'That's my class enemy'," said daughter Wenjia. With the rightward swing following Mao's death in 1976, Pu Quan - and China's cultural commissars - retreated to an idyllic vision of a past China: misty mountain gorges, rushing rivers, pine trees on crags, and delicate bamboo. His paintings were hung in the Great Hall of the People and the Zhongnanhai leadership compound, and Pu Quan himself was given a prestigious sinecure in his last few years.

Once rulers of China, the Manchu are now just one of 55 "minority peoples", numbering about 10 million. About 250,000 live in Beijing, but few can now read the Manchu script that adorns the former imperial palace, or speak the Manchu language. Under the Manchu system of succession by a male relative of the next generation, Jin Yuzhang is the heir-apparent, the family says. But Mr Jin (who was not given the Pu family name to head off possible discrimination) is happy to have risen only as high as vice-mayor of Beijing's Zhongwen district.

He has not joined the Communist Party, preferring to work as a "non-party democratic member" of local committees on political affairs and ethnic harmony. But his wife is a member, and his daughter is in the Communist Youth League. He thinks the former royals have fared well since the 1949 revolution, suffering less than they did under the Nationalists. "Most of the family have gained proper jobs to raise themselves by their own efforts," he said, adding: "Compared to ordinary people, our lives have been better. My next brother even has his own car."