Bao Tong recalls the events of 1989
Bao Tong was the most senior official imprisoned following the Tiananmen massacre - and he has still not regained his full freedom.
The 76-year-old was released from jail in 1996, but since then has been under constant house arrest.
Security officials monitor his every move; they follow him whenever he leaves his home, even on trips to the local supermarket.
Visitors to his flat, including a steady stream of foreign journalists, have to register with security officials on guard at the entrance to his apartment block.
He has now been forced to leave Beijing by the authorities until after the Tiananmen anniversary.
"I've had to adapt to this life, but this kind of situation is not uncommon in the history of the Communist Party," he told the BBC in an interview at his home before leaving Beijing.
Bao Tong was once at the apex of China's political system. In 1989 he was a secretary to the party's chief Zhao Ziyang and was pushing for more radical reforms in China.
Another man close to Zhao at the time was Wen Jiabao, whose career did not end in 1989. He is now the premier of China.
Mr Bao, born in Zhejiang Province, was arrested just days before the Tiananmen massacre.
He was accused of releasing the news that Zhao, who was then the party's general secretary, had been sacked.
Mr Bao denied the charge, but was kidnapped and taken to Beijing's notorious Qincheng Prison, reserved for political lawbreakers.
Many believe he was arrested because of his sympathy towards the goals of the student protesters.
At his trial in 1992, Mr Bao was sentenced to seven years in prison. Because of the time he had already served, he was released four years later.
Since then he has been living a relatively quiet life in Beijing under house arrest. "I've been eating and sleeping," he said in answer to a question about what he had been doing to pass the time.
He survives because of financial help from his wife and two children - and because of a stipend paid monthly to him by Beijing City Government.
Bao Tong never had a chance to speak to Zhao Ziyang after the massacre
The former high official was paid 500 yuan ($73, £48) "emergency living assistance", but that was increased to 2,000 yuan in 2007.
With time on his hands, Mr Bao often thinks about the course China has taken since 1989. He believes it would have been a very different place today if the reformers had won.
"What I feel most guilty about is that the 4 June incident happened while I was one of those tasked with bringing in political reform," he said.
To remind him of his time in power, there is a picture of his former boss Zhao Ziyang on a cupboard in his living room.
The party's former general secretary was put under house arrest after the Tiananmen massacre and Mr Bao never had chance to speak to him again. Zhao died in 2005 without being rehabilitated.
But Mr Bao has managed to honour his former boss by helping to prepare Zhao's memoirs, which have just been published.
Despite his regrets, Mr Bao believes the Communist Party's official verdict that the protests were a counter-revolutionary rebellion will be reassessed.
"I believe this day will come eventually, but I don't know whether it will come sooner or later."
Bao Tong was speaking to the BBC's Michael Bristow in Beijing.