Russian dissident Alexey Navalny, who died earlier this year in a remote penal colony, predicted the reign of President Vladimir Putin would eventually “collapse”, describing it as based on “nothing but lies”, according to his posthumous memoir set to be released later this month.

The 47-year-old opposition politician was seen as Putin’s fiercest political foe, who managed to galvanise the country and organise mass anti-Kremlin protests against abuse of power and corruption in recent years.

In excerpts from his book, Patriot, published in The New Yorker magazine on Friday, Navalny had also resigned to the possibility that he would spend the rest of his life in prison and die while in detention.

“I will spend the rest of my life in prison and die here,” he wrote on March 22, 2022.

“There will not be anybody to say goodbye to … All anniversaries will be celebrated without me. I’ll never see my grandchildren.”

Navalny was serving a 19-year prison sentence on “extremism” charges in an Arctic prison when he died on February 16.

His imprisonment and eventual death drew widespread condemnation, with many blaming Putin.

In April, his widow Yulia Navalnaya revealed that her late husband had started to write a memoir in 2020 after he had been poisoned by what Western doctors said was a nerve agent and was flown to Germany for medical treatment.

The Kremlin denied any state involvement in his death while in prison. When he was alive, he was also dismissed by Putin and his political allies as a marginal United States-backed troublemaker out to destabilise the country.

Navalny was arrested in January 2021 upon returning to Russia after suffering a major health emergency from being poisoned in 2020.

“The only thing we should fear is that we will surrender our homeland to be plundered by a gang of liars, thieves, and hypocrites,” he wrote on January 17, 2022 in his account of his last years.

Navalny also insisted that corruption was destroying the state, adding that “the best way to elect leaders is through honest and free elections.”

He said those who are currently governing Russia “have absolutely no ideas” and that “their only goal is to cling to power.”

“Lies, and nothing but lies,” he wrote of his country’s power structure under Putin, adding that “it will crumble and collapse.”

“The Putinist state is not sustainable,” he predicted in his book, which is set to be published on October 22.

“One day, we will look at it, and it won’t be there. Victory is inevitable.”

In a last entry dated January 17, 2024, about a month before his death, Navalny wrote: “It turned out that, in Russia, to defend the right to have and not to hide your beliefs, you have to pay by sitting in a solitary cell. Of course, I don’t like being there. But I will not give up either my ideas or my homeland.”

New Yorker editor David Remnick called Navalny’s writing “inspiring, emboldening”, and wrote that it was impossible to read his prison diary “without being outraged by the tragedy of his suffering, and by his death”.

“Navalny writes with a fierce moral clarity about the inhumanity of Vladimir Putin’s regime, and about the power of its opposite force – the humanity of his fellow countrymen,” Remnick said, of the prose “that is direct, precise, and, in the face of unimaginable isolation, mordantly funny”.

“Some people collect stamps. Some collect coins. And I have a growing collection of amazing court trials,” Navalny wrote.