Donald Tsang Yam-kuen, the only chief executive jailed before his conviction was quashed, said he was tortured by distress, insomnia and anxiety during his time in prison that no words can describe.
Tsang, 74, was originally sentenced to 20 months' imprisonment - later reduced to 12 months on appeal - for misconduct in public office. He actually served eight months before his name was cleared when the Court of Final Appeal overturned his conviction and sentence last month.
Speaking in a Catholic sharing session yesterday, he recalled his ordeal in a tiny, windowless cell at Stanley Prison - one of the SAR's six maximum security facilities.
"I've never thought I'd be investigated by the Independent Commission Against Corruption or even convicted of corruption offenses," he said. "It was unbelievable. All of my integrity and honor as a civil servant had become nothing in one moment."
He continued: "I woke up in the middle of the night one time. I lost all concept of space and time. My whole body was shivering. I screamed uncontrollably, looking for my wife."
He said he had 15 minutes to shower each day, and could only run on the rooftop for less than an hour every week. His faith "allowed me to see the light in the dark prison cell."
Coming from the grassroots, Tsang joined the civil service under British rule and became over-confident after he was named the first Chinese financial secretary in 1995, before being made the SAR's chief executive in 2005.
"I've been overconfident in my abilities and forgot to seek wisdom," he said. He now believes "genuine improvement in life does not come from climbing up the ladder, but in significant descent."
He noted that people only benefited from Jesus Christ blending in with the crowd, and Mother Teresa serving the poor in India.
Tsang thanked his wife, Selina Tsang Pau Siu-mei, for backing him through the ups and downs in nearly 50 years of marriage.
"When I was in prison, I treasured the chance to meet my wife for 30 minutes every week, as I often cried when the sessions ended," he said. "My wife is very important to me. I can't live without her."