All around Beijing, the scars are still evident. Older people talk of a climate of fear, of the terrible deeds carried out by the teenage Red Guards as they patrolled the streets and knocked on doors, looking for class enemies.

These zealous youngsters were acting on the orders of Chairman Mao Zedong, the founding father of the People's Republic, who orchestrated a Great Proletarian Cultural Revolution that tore through China a half century ago.

The Cultural Revolution was one of the darkest periods of recent Chinese history, when Mao unleashed a period of ideological frenzy that destroyed millions of lives.

Intellectuals and lawyers were driven into the countryside. At “struggle sessions” in city squares, teachers were forced to wear dunce hats. Children informed on their parents for even slight deviations from ideological standards.

Mao exhorted the Communist Party to rid society of "members of the bourgeoisie threatening to seize political power from the proletariat" and the decade-long violent class struggle only ended, 40 years ago, with the death of the Great Helmsman.

The Cultural Revolution whipped like a storm through a land still shuddering from the Great Leap Forward in 1958, a disastrous campaign of agricultural collectivisation that killed millions.

The stated aim was to destroy the "Four Olds", or the "Four Old Things"– Old Customs, Old Culture, Old Habits and Old Ideas. Terrible stories abounded. There were tales of cannibalism in Guangxi province where "bad elements" were publicly butchered and more than 70 victims were eaten in Wuxuan.

Reign of terror

When does a reign of terror actually begin? The historian Frank Dikötter, in his searing new book, The Cultural Revolution: A People’s History 1962-1976, dates the beginning of the event to June 1st, when an editorial in the People’s Daily called on its readers to “Sweep Away All Monsters and Demons!”

“It was a bold project, one that aimed to eradicate all traces of the past. But behind all the theoretical justifications lay an ageing dictator’s determination to shore up his own standing in world history,” Dikötter writes.

“Like many dictators, Mao combined grandiose ideas about his own historical destiny with an extraordinary capacity for malice. He was easily offended and resentful, with a long memory for grievances. Insensitive to human loss, he nonchalantly handed down killing quotas in the many campaigns that were designed to cow the population,” he says.

Others say it really began on May 25th, 1966 at Peking University, when Nie Yuanzi and others posted "big character posters", which had been used as a means of protest and propaganda throughout the ages, claiming the university was controlled by bourgeois anti-revolutionaries.

Many Chinese could not tell the Cultural Revolution apart from the anti-Rightist campaign which began in 1957, and which devastated the intelligentsia as Mao hunted down his political enemies.

That campaign was led by, among others, Deng Xiaoping, who during the Cultural Revolution subsequently fell foul of Mao and was banished from Beijing. Deng's son "fell" from the window of a police station, and was paralysed.

Xi Jinping’s father Xi Zhongxun fell foul of Mao and was banished to the countryside but the current president and party leader is reluctant today to criticise Mao.

No proper assessment

The Communist Party uses the official formulation that Mao was “70 per cent right and 30 per cent wrong” and has never permitted a proper assessment of what happened during the period.

In 1981, the party said the Cultural Revolution was a period of internal turbulence “wrongfully started by the leadership and used by counter-revolutionary elements”.

Children are still taught little about it in school and generally parents are unlikely to speak of happened to them.

In March, there were calls by the former culture minister Wang Meng for the party to "further explain" the Cultural Revolution, but he was told to toe the party line. "Reflections are normal . . . but they should not add or change the official political verdict," ran an editorial in the Global Times newspaper, a nationalist paper published by the same group as the Communist Party official organ, People's Daily.

A recent concert in the Great Hall of the People in Beijing featured Cultural Revolution songs such as Whole World Should Unite to Defeat the American Invaders and their Lackeys. The event was staged by key organisations within the ministry of culture, but they claim they were deceived about the concert’s political intentions by the organisers.

There is always a possibility the Cultural Revolution could return in some form or other, and there are leftist voices who call for such a development.

For older people, the fast pace of economic reform has led to yearning for a period before the days of BMWs and gold watches, a time when there was greater social equality and solidarity.