As Chinese students marched to demand democracy and an end to corruption, party elders were summoned to the home of the country’s paramount leader, Deng Xiaoping.

The wizened veteran listened to moderates, including the general secretary of the Communist Party, Zhao Ziyang, urging dialogue with the students, whose protests were seen as the greatest threat to date for the party.

Then, without even calling a vote of the most powerful body in China, the Politburo Standing Committee gathered there, Deng summarily imposed martial law. The army was called in and the student protests would be brutally crushed by tanks and troops in Tiananmen Square.

Now, on the 20th anniversary of the bloody suppression of the protesters, Zhao’s memoirs — painstakingly reconstructed from hours of tape recordings smuggled out by supporters — provide a unique glimpse of the deep divisions within the Chinese leadership. The first memoirs made public by such a highly placed party official will enrage today’s leaders because of his assertion that Western-style democracy is essential if China is to avoid future bloodbaths.

Times Archive, 1989: Bravery, hatred and ongoing carnage

At noon yesterday, when tanks started moving along the Changan Avenue, I watched as a man in a white shirt ran from a crowd

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• Times Archive 1989: Bravery and hatred

The record made by Zhao — who resigned, was purged and held under house arrest for almost 16 years — is to be published this month as Prisoner of the State: the Secret Journal of Zhao Ziyang. So sensitive is the document that its existence was kept a closely guarded secret until days before publication.

Speculation had been rife during his house arrest and after his death in 2005 as to whether the man with the most intimate knowledge of the behind-the-scenes machinations that led to the Tiananmen Square crackdown on June 3-4, 1989, had provided his own account of the dramatic days.

In the book, Zhao describes the secret meeting of the Politburo Standing Committee. “At that moment I was extremely upset. I told myself that no matter what, I refused to become the General Secretary who mobilised the military to crack down on the students,” he wrote. “On the night of June 3rd I heard intense gunfire. A tragedy to shock the world had not been averted.”

Troops backed by tanks entered Beijing to end weeks of student demonstrations. Zhao’s account confirms the bitter power struggle behind the scenes as the students occupied Tiananmen Square, and the deep rivalries between reformists and hardliners, as well as the crucial role played by Deng in the decision to use force.

The memoirs project was so secret that Zhao’s top aide, Bao Tong, who was jailed for seven years after the protests, told The Times that he learnt of their existence only after Zhao’s death. “I knew he wanted to write something. I knew he would want to leave some record of his work but it was extremely difficult because he was under constant surveillance,” he said. Mr Bao said that there was no doubt about the authenticity of the memoirs. “This is an extremely valuable document for China and for the West,” he said. Zhao left the memoirs on 30 one-hour tapes that he recorded in about 2000. Mr Bao said that it had been impossible for the disgraced party chief to make the recordings before 1999, but after that he had found a way to bypass those watching and listening to him.

The recordings include conversations in which he answers questions as well as sections that are apparently dictated from a now-vanished text. The tapes took Zhao about two years to make and he then found a way to pass them clandestinely to trusted friends. The materials were gathered together after his death, but much of the process remains a secret to protect those involved.

Mr Bao said that to protect Zhao’s family, they had been unaware of the memoirs. “If the authorities want to pursue someone for political or legal responsibility for these memoirs then I will bear everything,” he said.

The memoirs were translated and edited by Mr Bao’s son and daughter-in-law, Bao Pu and Renee Chiang, and the US journalist Adi Ignatius. He told The Times: “Zhao did this all secretly but he knew what he was doing: getting the final word on what really happened 20 years ago.”

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