There is often little difference between night and day in the remote Russian town of Kharp.

Sitting above the Arctic Circle, it's a part of the world that spends most of the year shrouded in near-constant darkness.

Yet, despite the bleak surrounds, Alexei Navalny still managed to make sardonic light of his new prison location.

"I'm your new Santa Claus," the jailed Russian opposition leader posted on X on December 26.

The Kremlin critic had just been transferred to the region's notoriously brutal IK-3 "Polar Wolf" penal colony.

"I now live in the Arctic Circle," he said.

"I don't say 'Ho-ho-ho', but I do say 'Oh-oh-oh' when I look out of the window, where I can see a night, then the evening, and then the night again."

Navalny spent three years in Russian prisons, but the concrete cage in the mountainous far north is considered one of the country's toughest.

Analysts say it's designed to break inmates physically and mentally.

Prisoners reportedly endure beatings, medical neglect and stretches of time outdoors in wet clothes in below freezing temperatures.

Through social media updates, written and posted by his lawyers, Navalny shared some of the conditions he faced at the "special regime" prison up until his mysterious death on February 16.

Through his signature dark humour and irony, the 47-year-old didn't want his treatment and torture to be forgotten.

The 'highest level of isolation'

Commonly known as "Polar Wolf", penal colony 3 (IK-3) was founded in the 1960s as part of what was once the Gulag system of forced Soviet labour camps.

Located in the Yamal-Nenets region, about 1,900km north-east of Moscow and 60km north of the Arctic Circle, Kharp itself was built by Gulag prisoners.

There are around 700 such penal colonies across the country that are part of "an incredibly brutal system," Robert Horvath, a specialist on Russian politics at LaTrobe University, told the ABC.

"The conditions are appalling and Navalny ended up at one of the worst outposts of this system."

The prison was strategically built in an area "where there's nothing else", Professor Horvath said.

It's surrounded by mountains and tundra in a frozen landscape that makes it impossible to escape.

"It is almost impossible to get to this colony; it is almost impossible to even send letters there," Navalny's chief strategist, Leonid Volkov, said on X last month.

"This is the highest possible level of isolation from the world."

Loading...

Navalny, who was among Russian President Vladimir Putin's most prominent critics, was first jailed in 2021 for 11-and-a-half years on fraud and other charges he said were bogus.

Last year, he had almost two decades added to that sentence for various offences, including funding extremism, which many observers described as politically motivated.

IK-3 typically houses inmates convicted of grave crimes, but it has held other political prisoners. 

Platon Lebedev, a Russian businessman with ties to exiled former oligarch Mikhail Khodorkovsky, served eight years at "Polar Wolf" for tax evasion, money laundering and fraud.

He is believed to have been a victim of a politically motivated trial.

Torture in freezing conditions 

Temperatures in Kharp fall below minus 30 degrees Celsius in the long cold months that make up most of the year.

And short bouts of summer are searingly hot, attracting mosquitoes and lice.

Navalny joked about the freezing temperatures in a post on the Telegram messaging app in early January.

"It has not been colder than -32°C yet," Navalny said.

"Nothing quite invigorates you like a walk in Yamal at 6:30 in the morning."

He posted a picture of his concrete-walled walking yard, which was 11 steps long and three steps wide.

Rights activist Olga Romanova told Radio Free Europe that a former inmate had spoken about various kinds of cold torture.

The man gave testimony saying inmates were forced to stand outside for up to 40 minutes in -40°C wearing minimal clothing.

If one person moved, the whole group was doused with water.

Stints in solitary confinement

Solitary confinement is common in the colonies and enforced for minor offences.

A spokesperson for Navalny said in late January he had endured 10 days of solitary confinement for "incorrectly introducing himself" to a guard.

Kira Yarmysh said on X that it was the 25th time Navalny had been placed in solitary confinement since he was jailed in February 2021.

She added that he had spent 283 days in such conditions.

Navalny spent months in and out of solitary confinement in the IK-6 penal colony where he was previously detained for nearly two years.

At IK-6, which is around 230km east of Moscow, Navalny was not allowed visitors and only one parcel permitted per year.

He was granted one 90-minute walk per day, with his hands cuffed behind his back.

Loading...

Sharing cells with sick inmates

At IK-3, Navalny was at times forced to endure stints with cellmates who were mentally and physically unwell.

In January, he posted about being placed with a cellmate with severe mental illness who would yell for "14 hours during the day and three hours at night".

He described the scream as "growling" and "guttural", saying it was similar to videos online that show people who believe that they are possessed by demons and devils.

"This system often uses other prisoners as a weapon," Professor Horvath said.

"Being in a cell with a mentally ill prisoner who screams at the top of his lungs in the middle on the night leads to extreme sleep deprivation, which itself is a form of torture."

Navalny suffered health issues throughout his time in prison, and had effectively returned from the dead after he was poisoned with a Soviet-era nerve agent in 2020.

Guards played on his health vulnerabilities by making him share a small cell with an inmate with gastric issues and diarrhoea.

He was also placed in a cell with a prisoner with serious tuberculosis, an infectious disease that is a particular threat to people whose health is already fragile.

Pro-Putin propaganda

Navalny also disclosed that he was forced to listen to a pro-Putin pop singer at five o'clock every morning.

He said his morning regime consisted of listening to the Russian national anthem before being played "I am Russian," a patriotic song performed by a singer called Shaman.

"The singer Shaman came to prominence when I was already in prison so I could neither see him nor listen to his music … Of course, I was curious to hear it," he sarcastically wrote on X.

"And here, every day at five o'clock in the morning, we hear the command: 'Get up!' followed by the Russian national anthem and then immediately afterwards, the country's second most important song is played — 'I am Russian' by Shaman."

Navalny revealed to the New York Times in an interview in 2021 that one of the most maddening parts of his imprisonment so far was being forced to consume Russian propaganda.

He said he would sit through more than eight hours a day of state TV and propaganda films with guards yelling at him if he would start to nod off.

Professor Horvath said the gulag system Navalny endured had not been seriously reformed during the years of that followed the collapse of the Soviet system.

"But it's certainly making a comeback now," he said.