Mr Navalny was convicted of establishing and supporting an extremist organization. He disputes the allegations.

He had previously been sentenced to nine years in prison for parole breaches, fraud, and contempt of court. The accusations are commonly perceived as politically motivated.

The trial took place at a distant correctional colony where he has been detained since 2021.

The Kremlin’s most vociferous opponent will serve his sentence in a “special regime colony,” as requested by Russian official prosecutors.

Such institutions, which are even more restricted than a high security colony, are usually designated for serious criminals, re-offenders, and those sentenced to life in prison.

There, he will most certainly face even more isolation, with even more limits on communication with the outside world.

He may also get fewer visitors than usual, including his family and legal team, and may be subjected to prolonged periods of solitary confinement.

Following the conviction, Mr Navalny remained defiant in a statement to supporters posted on X (previously known as Twitter). “You, not I, are being terrorized and robbed of the will to resist.” Putin must not achieve his objective. “Do not give up the fight,” he wrote.

The phrase “behind closed doors” seemed an understatement in this court case.

Alexei Navalny was tried at the high-security jail where he is presently detained, with the hearings closed to the press and public.

The BBC was permitted into Penal Colony Number 6 in Melekhovo, 150 miles east of Moscow, for the verdict, when a hall was converted into a makeshift courtroom.

We packed into a small room termed the “press centre” with other journalists to watch proceedings on a television screen. We were not permitted to enter the improvised courthouse (a jail hall) where the judgement would be proclaimed.

Alexei Navalny appeared at ease as he entered the courtroom and sat at a table. There was no drama in this circumstance for him: in a message posted for him on social media yesterday, Russia’s most renowned opposition figure stated unequivocally that he fully expected a “Stalinist” punishment.

On the video screen, there was an image. However, the audio stream from the courtroom was low and sporadic.

When the court found Mr Navalny guilty and sentenced him, it was unclear to the journalists watching and hearing how long the new prison term would be.

Later, in a social media message for him, Mr Navalny verified the statistic.

“I spent nineteen years in a colony run by a special regime.” The figure has no significance. I am completely aware that, like many political prisoners, my sentence is life in jail. “Life is measured by either my or the regime’s lifespan.”

Alexei Navalny: Russia’s imprisoned yet outspoken opposition leader Putin criticizes Navalny and Russia’s unique poison arsenal.
The latest sentence “raises serious concerns about judicial harassment and the instrumentalisation of the court system for political purposes in Russia,” according to UN human rights head Volker Turk.

Mr Navalny might yet face more charges. He claims that investigators have informed him that he will face another trial on terrorism-related accusations.

Mr Navalny has spent more than a decade attempting to uncover corruption at the core of Russian authority. His video investigations have been viewed by tens of millions of people online.

He appeared to be the only Russian opposition leader capable of mobilizing big crowds across Russia to participate in anti-government rallies.

However, in 2020, he was poisoned in Siberia by a nerve toxin, which Western laboratories later proved.

A subsequent article by the investigative website Bellingcat and the Russian news site The Insider implicated multiple FSB operatives in the attack.

Mr Navalny returned to Russia in 2021 after recuperating from the attack, despite threats that he may be arrested. When he arrived at Moscow’s Vnukovo airport, he was apprehended instantly.