Secretary for Financial Services and Treasury Frederick Ma Si-hang was forced to offer a public apology one day after refusing to do so in September. He said he had no knowledge of a consultation document prepared in July which proposed delisting the so-called 'penny stocks'. The proposal triggered panic dumping and wiped more than $10 billion off the market value of shares.

The biggest challenge to the system came when it was revealed that the financial secretary had bought a luxury Lexus 430 car before announcing a hefty rise in the first-registration vehicle tax in his March budget. Mr Leung has defended his act as an oversight.

Despite intense pressure to hold the finance chief responsible, Chief Executive Tung Chee-hwa refused Mr Leung's offer to resign, while criticising him for showing 'gross negligence'. A no-confidence motion moved in May by legal sector legislator Margaret Ng Ngoi-yee was blocked by pro-government parties.

Mr Tung himself also faced and survived an unprecedented motion calling for his resignation in May. Observers said that although the motion, moved by independent Albert Chan Wai-yip, was voted down by pro-government parties, it damaged his already-dented credibility.

The system's most recent test came during the Sars outbreak, when Secretary for Health, Welfare and Food Yeoh Eng-kiong was under pressure to resign for the government's failure to contain the virus at an early stage. Mr Tung has stressed that a government review panel, led by Dr Yeoh himself, will probe the health system but will not apportion responsibility.