Along with Wen's latest push for political changes, Zhou's proposed reform blueprint reflects mounting public aspirations among mainlanders for democracy and human rights.

In an article published in the latest edition of Yanhuang Chunqiu, widely seen as the mainland's most outspoken reformist magazine, Zhou said the party could not afford to waste another opportunity to break the decades-long deadlock on political reform, given what he said would be the dire consequences of further delays.

Despite China's dazzling economic success and rising global clout, Zhou offers a trenchant analysis of the mounting problems the country is facing, which he said could largely be attributed to long-overdue political reform.

'We must remain sober-minded about the so-called China model, which features a combination of high investment, high energy consumption, heavy pollution, low income, low land prices and poor human rights, and is hardly applicable,' Zhou said.

He said that inherent flaws with one-party rule - namely, an overconcentration of political power and the absence of checks and balances - had helped cause rampant official and judicial corruption and given rise to irrational decisions and the blind pursuit of growth at the expense of people and the environment. Along with the powerful interests groups, such an authoritarian political system - also known as a juguo, or 'whole nation', system - is capable of wreaking 'immeasurable, irreversible havoc on society' at the cost of the government's remaining credibility, Zhou warned.

He also voiced concerns about the ever-widening gap between the rich and poor. China has one of the world's highest Gini coefficient figures - a measure of inequality in income distribution - estimated at 0.48 by the World Bank, well above the warning level of 0.40 for social unrest. As a result of the yawning wealth gap, corruption, environmental degradation, forced evictions and widespread discontent at injustices, the country has seen an explosive increase in petitions, demonstrations and protests.

According to Zhou, the number of mass incidents, a euphemism for public protests on the mainland, have grown more than tenfold in the past two decades to more than 90,000 a year, while the number of petitions reached an alarming new high of 9.7 million last year.

Zhou said the widespread despair and disillusionment had driven people to resort to more violent ways of airing their grievances in the past year, such as three bombings of Anhui government buildings over land grabs in May, two separate mass riots between migrant workers and locals in Guangdong in June, and the largest unrest by ethnic Mongols in Inner Mongolia over mining disputes and environmental degradation in May. He also lashed out at the recent revival of the Maoist left, which prevents a thorough review of the lessons from the Cultural Revolution and threatens to jeopardise reform and political liberalisation.

The resurgence of nationalism, along with the rather clumsy diplomatic decision-making process that is largely driven by outdated ideologies and the 'ostrich approach', have further undermined Beijing's ability to cope with growing hostilities and diplomatic challenges abroad that accompany China's rising global influence, he warned.

Intriguingly, Zhou also expressed admiration for former Kuomintang leader Chiang Ching-kuo, whose name is rarely mentioned by the mainland's official media. Chiang took bold moves towards democracy in his final years in the 1980s that ushered in Taiwan's democratic transformation process.

Despite the detailed list of mounting political, social and economic woes, Zhou cautioned against radical changes, which he said would lead to instability and upheavals.

Instead, he mapped out a timetable for China's political reform, consisting of three stages, towards the end of the 16,000-word essay.

China has basically completed its economic reforms. Social reforms - launched in 2004 and the second stage of Zhou's plan - would last until 2021, and are aimed at making essential preparations for substantial political reforms, Zhou said. After establishing a social security system, relaxing control on social groups, addressing pollution problems and implementing reforms of education, health care and housing prices, Beijing would be ready to kick-start political reforms such as constitutional democracy, rule of law and resolving the overconcentration of political power in the government.

Zhou said that all the major goals of the reforms should be achieved by 2049, coinciding with the centenary of the founding of the People's Republic. Analysts said it remained unclear whether Zhou's proposal had won the backing of party elders or other top leaders.

Zhou, 72, is renowned for a series of pro-reform articles supporting the late paramount leader Deng Xiaoping in the early 1990s, and is believed to be associated with party elders, including former premier Zhu Rongji.

Dissident liberal intellectual Chen Ziming said Zhou's proposed plan on political reforms basically echoed what many intellectuals had advocated in the '80s and '90s.

And given the lack of progress to date, Chen and other analysts are downplaying the possibility of any substantial political reforms in the coming decade, considering the high stakes of such changes.

'We have seen liberals within the party appeal for further reforms from time to time, but none of these calls seems to have made any difference,' Chen said.

Of Zhou's reform timetable, Professor Yuan Weishi of Sun Yat-sen University said: 'It may be a good aspiration, but it is very unlikely that things will occur according to his timetable, especially considering chance that often play important roles in social progress.'