Named after the Qing dynasty palace in northwest Beijing that was sacked by foreign troops in 1860, the play presents a subversive thesis: The Chinese, rather than foreigners, were to blame for the destruction of the Yuanmingyuan, long held as a symbol of architectural and philosophical perfection.

'Each of us is responsible for the death of that dream,' says Zhang, an independent director, musician and poet.

The Communist Party has for decades painted the sacking of the Yuanmingyuan as evidence of foreign persecution, and the issue remains sensitive today. In January, authorities closed Bingdian, a popular weekly published by the Beijing Youth Daily, and fired its editors for running an essay by respected historian Yuan Weishi, which argues that mainland textbooks are wrong about the sacking.

Instead, Yuan says they give schoolchildren a biased account of events that could produce a generation as xenophobic as the Red Guards.

Zhang, too, dismisses simplistic portrayals of China as victim. To be sure, foreign soldiers started the plunder at Yuanmingyuan, but ordinary Chinese and warlords are guilty of pillaging, too.

And so the first act of his play opens with three Chinese who direct a haughty foreign soldier to the palace, where they join the looting. Subsequent acts reveal further exploitation through the decades, by students in the earlier days of communist rule and then local officials who scheme to profit from the park created from the remains of Yuanmingyuan.

Even filmmakers take part, coating trees with yellow paint - a reference to similar actions by director Chen Kaige during filming of The Promise that infuriated environmentalists. 'Burning the Yuanmingyuan was only the beginning,' says Zhang. 'After it was burned down, who stole all the left-over timber? Who stole the stone? Why are four pillars all that is left from the original palace?'

However, what prompted Zhang to write his two-hour-long play was a proposal last year by district officials to line the lakes at Yuanmingyuan with plastic sheeting to prevent seepage and cut water costs. Public outrage forced the government to hold its first public environmental hearing, and the plan was eventually abandoned. '[The officials] tried to destroy the environment totally. It was the same as what the British and the French did,' says Zhang says.

Onstage, a giant plastic sheet symbolises that move, and ignorant, clownish officials play it for laughs.

The play focuses on the destruction of the environment, drawing a clear connection between the government's development policies and the foul air and water that choke the mainland today. Under a one-party system, Zhang says, people have no choice but to fall in with official plans. 'Why aren't there 10 different ways of being in China today? Why is there only one?' he asks.

To illustrate the scale of environmental damage, 100 activists move through the audience, spraying water, unfurling banners and dropping leaflets that read 'The Crisis is Here!' They deliver a string of frightening statistics: 300 million people have no access to safe drinking water; more than 400 million endure badly polluted air.

At the end of the play, a character lectures viewers: 'Yes, we did it. But who among you is not guilty?'

Such ecological concerns won Zhang's production backing from the State Environmental Protection Agency - a crucial factor that he says helped shield the play from censorship. Yet the environmental crisis is a surface issue.

'It's just a symbol,' says Zhang, a Christian, who sees the real problem as something more intangible and important - the people's lack of faith.

Zhang says many people are dispirited, drifting rudderless in a sea of greed and development frenzy. The destruction of the Yuanmingyuan, the lovely dream of gardens and palaces that Victor Hugo wrote about, symbolises that. 'People have no faith, no dream,' he says.

Disenchanted with communist ideology, he says, people not only spurn socialist ideals but also faith. That leaves them engrossed in material pursuits. 'Everyone leaves their dreams outside the door because they're busy making money. Yet how can we get paradise back? If it's not in your heart, it will never come back.'

A non-conformist, Zhang spent three years in a Jiangsu provincial jail for joining student demonstrations that swept the mainland in 1986. He says he was lucky to be released in April 1989. 'If I'd still been in jail during June 4 [crackdown on the Tiananmen protests] they would never have let me out.'

Zhang supported himself in the early 90s busking with his guitar. That paid too poorly and he switched to work in an advertising agency in Beijing. But he kept his hand in music, and film director Zhang Yimou later invited him to compose music for Shanghai Triad - an assignment that gained him entry into arts circles.

The mainland's rush towards development carries a group mentality similar to that which led to the disasters of the Cultural Revolution, says Zhang.

What China needs above all is to learn to value the individual, he says. Or as one of the play's characters says: 'Before, class struggle was the most important thing. Now it's GDP.

'In China we are like a pancake: when we've burned one side, we flip over to the other. But never have we made human beings the most important thing.'

Zhang says he may have been allowed to put on such provocative material thanks to a loosening of official attitudes ahead of personnel changes at the 17th Communist Party Congress next year. That he was instructed to present Saint Confucius, a play banned in 2002, at an international theatre festival in Vienna last year suggests that some senior officials share his perspective, Zhang says.

Other theatre observers are less optimistic. Pointing to tighter restrictions in print and online media, some attribute censors' more relaxed attitude towards stage productions to their smaller reach. 'They don't really care much because they know not many people go to see it anyway,' says Beijing theatre producer Wang Zhaohui.