On Wednesday morning last week reporters gathered at the Shanghai Hall in the Great Hall of the People, where the city's delegation was meeting, eager to grab their only chance to get close to the mayor and ask him questions. Openness and transparency, however, were not much in evidence.

Journalists were allowed to hear only prepared speeches from a distance, separated from the city's officials by a cordon. Mr Han slipped out before the end of the meeting, before security guards expelled all reporters from non-Shanghai media.

Mr Han has repeated his openness and transparency dictum on many occasions. But on a personal level he appears to observe the golden rule of Chinese officialdom - keep a low profile and button your lip, particular in the politically sensitive run-up to a party congress.

This autumn's 17th party congress will decide Mr Han's political future, with the whole leadership expected to undergo a major reshuffle.

To be acting party secretary is a significant career boost for the mayor, with several former Shanghai party bosses having gone on to key jobs in Beijing, including former president Jiang Zemin , former premier Zhu Rongji , NPC chairman Wu Bangguo and Vice-Premier Huang Ju .

Analysts said Mr Han, a 53-year-old marked out as a rising political star, was picked to fill the top job to provide continuity and to calm nerves in the city's bureaucracy.

Since taking over as mayor in February 2003, observers say he has given a steady, but unspectacular, performance.

'Mayor Han has been in a leading position in the city for about 15 years and this has proved that he is capable of leading the city,' said Yuan Yixing , a Shanghai NPC deputy.

Analysts said it was possible Mr Han would be named permanent party secretary because there was almost no precedent for an acting party secretary not to be confirmed.

Nevertheless, Shanghai ended its annual legislative session last month without mentioning a change in the mayor's post to clear the way for Mr Han to be named party secretary.

The Shanghai party committee also ended its annual meeting recently, with Mr Han remaining the city's acting party secretary. Analysts said this indicated the central leadership had not yet decided whether to name a new party secretary for Shanghai or promote Mr Han to the top job.

A native of Zhejiang province , Mr Han has risen through the government and party ranks in Shanghai, where he has spent his entire political career. He previously served as executive vice-mayor and then vice-mayor.

An economics graduate from Shanghai's East China Normal University, he worked in the chemical and rubber industries, but mainly in party posts.

He has also served as secretary of the Shanghai Communist Youth League, head of Shanghai's central Luwan district, deputy secretary-general of the city government and chief of its planning commission.

Although the Communist Youth League is considered the key power base of President Hu Jintao , Mr Han owes a greater allegiance to the so-called Shanghai Gang, led by Mr Jiang. Mr Han is also considered a close ally of former bosses Mr Zhu and Mr Huang, who is tipped to retire this year because of health problems.

Observers said that since becoming acting party secretary, Mr Han appeared to have pledged allegiance to Mr Hu and increasingly toed Beijing's line on most policies.

Analysts said Mr Chen's sacking was a move by Mr Hu to crack down on the Shanghai Gang before the 17th party congress, but was also partly sparked by Mr Chen's refusal to implement central government policy directives aimed at taming an overheated economy.

Shanghai has boomed over the past decade, with the city government tending to ignore Beijing's attempts to cool the economy. Its emphasis on rapid growth and property development put city hall at odds with the Beijing leadership, who have been seeking to achieve balanced growth and address worrying economic disparities across the nation.

Mr Han also made bullish comments about the property market that may come back to haunt him but there has since been a change in tone, with him saying the municipal government would 'earnestly implement' the central government's macroeconomic control policies.

'Mayor Han has attached importance to the central government's policy to address disparity and has made efforts to do some practical work to help people in difficulties. The government under him has also stepped up measures to solve problems in property speculation,' said Sun Yunshi , an NPC delegate and secretary-general of the Shanghai municipal legislature.

Mr Sun, citing data from the National Development and Reform Commission, said Shanghai had seen the biggest housing price declines of 70 main cities last year.

'Shanghai is beginning to take every notice of central policy,' said another NPC delegate, who requested anonymity. For example, the day after Premier Wen Jiabao delivered his government work report to the NPC, Shanghai set its economic growth target for this year at 9 per cent, after 15 years of double-digit growth.

No one could have foreseen the tricky circumstances under which Mr Han was promoted to the mainland's most coveted local leadership post. His relative youth and clean image, however, will help his political rise.

Some top party leaders without obvious political affiliation consider Mr Han one of the party's potential future leaders.

Mr Han was only considered a 'junior member' of this Shanghai Gang and his link with the Communist Youth League might help him to distance himself from its decline, analysts said.

More likely, Mr Han might benefit from a political compromise between Mr Hu and the Shanghai Gang and rise further to become a member of all-powerful Politburo and secure a top position in Beijing.