Mr Huang, also known as Yu Qiwei , a former party secretary and mayor of Tianjin and minister of machinery industry, was a member of the party's elite Central Committee until his death in 1958. Yu Zhengsheng's mother, Fan Jin , was a vice-mayor of Beijing before the Cultural Revolution.

Born in 1945 in Zhejiang , Mr Yu attended Beijing's No4 High School, arguably the best school in the capital, and joined the party in 1964.

He graduated from the Missile Engineering Department of the Harbin Military Engineering Institute in Heilongjiang province in 1968.

Mr Yu began work at the Ministry of Electronics Industry and worked his way up the ladder during a 16-year career at the ministry, spending his last two years there as a deputy department head under Jiang Zemin , who was a vice-minister and then minister.

He then became an aide to Deng Pufang , Deng Xiaoping's eldest son, in running the China Welfare Fund for the Disabled and acting manager of the Kanghua conglomerate, which was later shut after allegations of corruption.

Soon after his move into the business sector, Mr Yu suffered a major blow which handicapped his career for years, and which is still likely to overshadow his promotion prospects in future, when his younger brother, Yu Qiangsheng , a senior intelligence officer in the Ministry of State Security, defected to the US in 1985.

The defection was said to have shocked party elders and triggered a tougher policy stance towards princelings, which left most of them in the cold for a decade.

Mr Yu was soon transferred to Shandong , starting as deputy party secretary in the open city of Yantai in 1995 and then rising to the post of Qingdao mayor in 1989 and party secretary in 1992.

During his 12-year stay in Shandong, especially his eight years in Qingdao, he did well in rebuilding confidence and received credit for fostering the country's top brands, such as Haier and Tsingtao Beer, and for relocating the city centre.

His success in urban development in Qingdao increased his profile in Beijing and established him as an open-minded reformer and a doer rather than just a talker, paving the way for further promotion.

Mr Yu was appointed construction minister in Zhu Rongji's cabinet in 1998 and supervised the mainland's controversial housing reform, which saw an end to the long-established socialist policy of providing housing to millions of state workers.

Unlike most senior cadres, who were evasive about social ills and the authorities' shortcomings, Mr Yu stunned the public with his outspoken criticism of dangerously shoddy construction on the majority of the mainland's building sites and Beijing's bad city planning.

He was sent to Hubei as party secretary in November 2001 and became a Politburo member one year later.

'Mr Yu has made some progress in Hubei, such as helping ease farmers' tax burdens and pushing for a pilot project to streamline overstaffed county and township government,' said Hu Xingdou , a Beijing-based political analyst.

Mr Yu also earned fame for his initiatives to carry out pilot political reform measures among county-level party organs to test direct elections and strengthen efficiency and supervision. Such reforms, though strictly small-scale, are rare in the 85-year history of the party.

But he has also had to put up with a harsh reality common in the central and western provinces: vast, economically underdeveloped rural areas and overstaffed local governments plagued by poor management and official corruption.

In August, the head of the Wuhan Intermediate People's Court, Zhou Wenxuan , was detained for allegedly taking bribes two years after 13 court judges, including his two deputies, were sentenced to prison terms for corruption. At least 40 other judges in the same court were also implicated in the country's largest judicial corruption case.

But Mr Yu has had to put on a brave face. 'Miscarriages of justice should not give excuses to attempts aimed at obstructing or jeopardising the authority of the legal system and stability,' state media quoted him as saying earlier this year.

Analysts said that despite his reformist credentials within the party, Mr Yu remained tough in dealing with dissent and troublemakers and upholding stability, toeing the line followed by President Hu Jintao and other top leaders.