Last summer a bald middle-aged man in a beige anorak stood in a Russian prison courtyard addressing dozens of inmates in blue overalls. “I represent the private military company Wagner — perhaps you’ve heard of it?” he said. His presence there was a sign of just how badly things were going for Vladimir Putin’s army in Ukraine: Yevgeny Prigozhin, himself a former convict turned billionaire businessman and friend of Putin, was trying to help the war effort by recruiting convicts into his private army.

Until then, this paramilitary force had served as an unofficial foreign policy tool of the Kremlin, providing Russian muscle to various dictators around the world, notably in Africa. At the start of the war in Ukraine some Wagner combatants had been sent to Kyiv in a failed attempt to assassinate President Volodymyr Zelensky. Prigozhin did not beat around the bush: if the prisoners agreed to sign up and survived for six months on the front, they would be free to go home with an official pardon. If they ran away, they would be put in front of a firing squad. “You have five minutes to make up your mind,” he told them.

A soldier leaves an office belonging to the private military company Wagner in St. Petersburg, Russia.

Since that video was shot, Wagner has managed to recruit more than 20,000 convicts and Prigozhin has assumed an increasingly prominent role in the war. Prigozhin recently said he was stopping recruitment from jails — stories about Wagner brutality and convicts being used as cannon fodder may have dampened prisoners’ enthusiasm for signing up. He also said the group would not be able “to carry out the scope of tasks that we would like to”.

Videos had surfaced on social media of him welcoming home the first batch of 200 recruits at the end of their six-month assignment. Other clips show Putin granting pardons and awarding medals for courage, delivered by goose-stepping guards.

The grim truth behind this theater, though, is that thousands of men from this “penal battalion” were slaughtered within days — or even hours — of arriving at the front. Many others have been executed by their own side. “They would round up those who did not want to fight and shoot them in front of newcomers,” says Andrei Medvedev, a Wagner recruit now seeking asylum in Norway. “They buried them right in the trenches that were dug by the trainees.”

If the prisoners agreed to sign up and survived for six months on the front, they would be free to go home.

Others who have been captured by Ukraine have described how commanders standing behind them with guns ordered them to run at enemy lines or be shot, in an echo of the Soviet executions of deserters from the battle of Stalingrad in the Second World War. Earlier this month, amid reports of plummeting morale, footage emerged apparently showing Wagner troops violently beating one of their own commanders with shovels. Nevertheless these “human wave” attacks appear to have made a difference, allowing Prigozhin to crow, for a while, about progress during the battle for the eastern Ukrainian city of Bakhmut while criticizing the Russian ministry of defence and “horrendous military bureaucracy” that had prevented Wagner from capturing the city by the new year.

Once little more than a useful tool for the Kremlin, Prigozhin has moved into another league — an increasingly powerful and independent figure who appears to relish life in the spotlight. He boasted in January that “Wagner is probably the most experienced army in the world”. The question many analysts are asking now is whether he might use it to push Putin from power.

Prigozhin’s influence and ambition have often seemed unlimited: in order to free rapists and murderers to fight in Ukraine he had to pull rank over various powerful groups that answer only to Putin, not least the FSB, the secret police. This has led commentators to conclude that the shaven-headed internet showman, who has turned tough talk and brutality into a personal brand, believes his moment has come. He is reported to be in the process of setting up a political party.

Wagner has recruited more than 20,000 convicts as Prigozhin has assumed an increasingly prominent role in the war against Ukraine.

But his decision to stop recruiting in prisons coincides with reports that the Russian army has now begun drafting convicts in the same way and may be a sign of boundaries being reimposed on Prigozhin.

Evidence that the Wagner boss, once known only for his slavish devotion to Putin, sees himself in the running to replace the president is likely to have put the Kremlin on edge: it has certainly put a chill down the spines of Moscow’s remaining liberal technocrats. “There is an atmosphere of deep foreboding in Moscow,” an intelligence source says. “There’s a general panic, along with rumors that Putin is preparing a ‘Noah’s ark’ for himself overseas in case he has to do a runner.”

Someone, though, is trying to hold Prigozhin accountable: as Ukraine and Russia prepare for a spring campaign, the UK-based human rights lawyer Jason McCue has launched his own offensive to bring the billionaire to book with a case before the High Court in London, seeking compensation for tens of thousands of Wagner’s victims. Other cases in other countries are expected. McCue is hoping to seize the group’s international assets as compensation for Ukrainians as part of a wider “lawfare” campaign around the world against the Russian war machine.

Last month the US government designated Wagner as a “transnational criminal organization”. This was a “step in the right direction”, McCue says. “But we should be branding them as what they are — a terrorist organization. They put explosives next to a nuclear plant in Ukraine. Who does that sort of thing other than a terrorist group?”

Prigozhin responded to the lawsuit with his usual brazen swaggering — he cheekily offered to finance the prosecution himself, saying, “McCue doesn’t have any money.”

McCue fired back an email: “I said, ‘No, we won’t take your money,’ and quoted those Ukrainian guys on Snake Island who refused to surrender to Russian forces — ‘Go f*** yourself.’ ”

Respected human-rights lawyer Jason McCue.

McCue, who is married to the Times Radio presenter Mariella Frostrup, was an early pioneer of lawfare, winning more than $1.2 million in various compensation claims for victims of despots and terrorist groups, from the Real IRA to the late Libyan dictator Muammar Gaddafi. He comes across more like a rock star than an attorney, with his stubbled face and colorful diction. “The thing about lawfare is that it allows you to f*** the other side strategically, to frustrate the Russian war machine,” he says. “We can be a thorn in their side, a pain in the arse.”

On a recent visit to Ukraine he was surprised to be hailed as a hero and savior. “They introduced me as ‘Dr McCue, international philosopher, defender of human rights and protector of the Ukrainian faith’. I thought, ‘Sometimes you don’t correct the interpreter.’ It’s quite nice — perhaps we can get T-shirts with that written on them.”

As part of a campaign to crowdfund legal actions, Ukraine has made McCue the protagonist of a TikTok video meme in which he is seen speaking at a press conference in Kyiv. “Where I’m saying lawfare will be a pain in the arse for Putin’s war machine, it’s been dubbed to, ‘I’m going to stick a rolling pin up Putin’s arse.’ My wife’s going, ‘What the f*** are you saying?’ ” Is he worried about retaliation? “Yes, it’s something we’ve got to think about,” McCue says.

For some of Russia’s most extreme nationalists, Prigozhin, 61, has become a kind of folk hero. The owner of a string of companies around the world, including a mining multinational, he is one of the country’s richest oligarchs. But that has not stopped him from ranting angrily on social media about rich Russians, “those who live abroad, raise children abroad, proclaim high values but nevertheless support the West”.

Prigozhin’s influence and ambition have often seemed unlimited.

It appears to go down well with the masses, just like his blunt-speaking appeal to the convicts. “He’s one of us,” a recruit was quoted as saying, noting that the Wagner boss had served nine years in prison. Prigozhin, for his part, has made clear why he’s interested in them: “I need your criminal talents,” he told them. It was a line that could have come from The Dirty Dozen, the 1967 American film about Allied officers recruiting violent prisoners to kill German officers in the war.

“A dog’s death for a dog” is how Prigozhin responded to a video of Wagner troops brutally beating a man.

Prigozhin’s “penal battalion” has echoes, too, of Adolf Hitler’s Dirlewanger brigade, whose criminals turned soldiers raped and murdered their way around Europe for the SS. It was named after Oskar Dirlewanger, its commander, himself a convicted rapist.

“You can find people in jail with a bit of form when it comes to violence,” says General Sir Richard Barrons, a former British army commander. Mercenaries in general are free to do “terrible things on the battlefield because they are not accountable. They can act with impunity.” He adds that Prigozhin sees himself as “an iconic figure doing the hard yards for the sake of his country. He is not a man put off by atrocities — he doesn’t care about any of that. He’s not an employer I would want.”

The story of mercenaries is long and bloody, from the “barbarians” who fought for the Roman Empire to the Italian condottieri armies of the Middle Ages. Guns for hire have helped to shape recent history too. A curious example is William Walker, an American adventurer who won a civil war in 19th-century Nicaragua to become the de facto ruler of what, for a while, came to be known as “Walkeragua”.

Today mercenaries prefer to be known as private military companies (PMCs) and they have proliferated everywhere. They are not protected by the laws of war — the Geneva conventions do not recognize them as legitimate combatants. But business is booming. “A lot of young men want to sign up without even having been in the army,” says one British soldier of fortune, who declines to be identified. “They’re after a life of adventure.” He insists Russian mercenaries are different, however: “Their morality is not ours.” He describes an incident off the Horn of Africa a few years ago. “The Wagner guys had caught some pirates. They tied them up, put them back in their boat, poured petrol over them and lit them. If you’d said something they wouldn’t have thought there was anything strange — ‘That’s what we do to pirates.’ ”

Prigozhin has made clear he has no qualms about his men’s extreme violence. “A dog’s death for a dog” is how he reacted to a video broadcast online of Wagner troops beating one of their comrades to death with a sledgehammer. The victim, Yevgeny Nuzhin, was a convicted murderer recruited by Wagner who had come under suspicion of passing information to Ukraine after being captured and sent home to Russia in a prisoner exchange. Prigozhin joked about the “excellent directorial work that’s watchable in one sitting”.

It was not the first Wagner murder by sledgehammer to have been captured on video. Wagner soldiers had used one in Syria years earlier to smash a prisoner’s wrists and ankles. They then dismembered and decapitated him, laughing as they burnt the remains. “They’re out of control, I don’t think it’s an isolated case,” says Denis Korotkov, a Russian journalist who managed to identify one of the killers as a former Russian policeman.

Atrocities have come to light wherever Wagner has operated. “We’ve been sounding the alarm about them since 2018, but nobody has been paying much attention until now,” says Sorcha MacLeod, a member of the UN working group on mercenaries.

A float bearing the inscription PUTIN’S DELUSION in the Rose Monday parade in Düsseldorf, earlier this month.

Last month the UN accused Wagner of “war crimes” against civilians in Mali, whose government has engaged the mercenaries to help win a long-running war against jihadists following the withdrawal of French forces early last year. “They’ve committed a whole range of human rights atrocities and war crimes, with people in their hundreds being killed in one attack on the town of Moura in March last year,” MacLeod says. “People were forced to dig their own graves before being summarily executed.”

Prigozhin appears to have learned cruelty from an early age. As teenagers, he and his friends were involved in a number of robberies and assaults in St Petersburg. Court documents relate how, one evening in 1980, they attacked a woman in the street. Prigozhin choked her until she lost consciousness so they could steal her gold earrings. Various other robberies were committed over a period of months until Prigozhin was arrested and sentenced to 13 years in prison. He was released in 1990, just as the Soviet Union was beginning to unravel, and decided to go into business as a hot-dog salesman.

Soon the roubles were piling up in his mother’s humble kitchen faster than he could count them. He acquired a stake in a chain of supermarkets and opened a restaurant, hiring a British hotel administrator who had previously worked at the Savoy in London to manage it. It became a magnet for pop stars and businessmen.

“They were tired of eating cutlets with vodka,” Prigozhin told a Russian society magazine. The city’s former mayor, Anatoly Sobchak, was a regular. So was his deputy, Putin, a KGB officer and native of the city.

After Putin became president in 2000, he invited the presidents Jacques Chirac and George W Bush to a second restaurant Prigozhin had opened on a boat. In pictures, Prigozhin is seen hovering in the background, an obsequious maitre d’. Putin was impressed. “He saw how I built my business starting from a kiosk,” Prigozhin told another magazine. “He saw how I was not above serving a plate.”

Prigozhin has been frequently spotted at the Russian president’s side, serving him lavish meals and earning him the nickname “Putin’s chef.”

The relationship brought rich dividends. He became known as “Putin’s chef”, his Concord company winning big catering contracts from the Russian state. The business was soon feeding schoolchildren and soldiers all over Russia.

Prigozhin became fantastically rich, with palaces and a private jet. Despite his habit of secrecy, a few details have emerged about his private life from photographs posted a few years ago by his two grown children on Instagram. One showed his son, Pavel, walking naked on the deck of the family’s 115ft yacht. Other pictures displayed a vintage, powder-blue Lincoln Continental, supposedly Prigozhin’s favorite car.

Among his daughter Polina’s pictures was a shot of the family’s wooded holiday compound in a resort town on the Black Sea. It has its own pier for the yacht and was built in a protected forest area where construction was supposedly banned.

“I need your criminal talents,” he told them.

After years of catering for the military, Prigozhin was reported to have pitched a plan to Putin about how to promote Russian interests around the world without implicating the Kremlin. Wagner was formed in 2014 with the co-operation of the GRU, the Russian military intelligence service, which provided a provincial training site near its own base, as well as equipment. The military spy chiefs apparently had no choice: the operation had been approved by “the boss” — Putin.

While Prigozhin flitted around in his jet, day-to-day leadership of this private army was left to Dmitry Utkin, a former officer in the GRU and “Spetsnaz” special forces. Russia says its goal is to “de-Nazify” Ukraine but may have a Nazi issue in its own ranks: Utkin is a committed neo-Nazi with SS symbols tattooed on his neck. The mercenary group took its name from Utkin’s call sign, “W” for Wagner, the German composer, a favorite of Utkin — and Hitler. A musical thread runs through the group’s operations: the mercenaries refer to their army as an “orchestra”; they are its “musicians”. But the performance is never harmonious.

One of their first gigs was the surreal annexation of Crimea in 2014, when the Kremlin left the world guessing whether the figures in combat fatigues with no markings who appeared on the peninsula’s streets — the “little green men” — were Russian. If not, who were they?

Officially, Wagner did not exist: private military companies are banned in Russia. But that did not stop Prigozhin from sending combatants into the eastern Donbas region of Ukraine later that year to foment separatism — part of a Kremlin plan to undermine the government in Kyiv.

Wagner’s next task was to set up in Syria in support of its blood-drenched dictator, Bashar al-Assad. Utkin was reported to have ordered his men to make the first sledgehammer video to inspire terror in the ranks of Assad’s rebel enemies. The Wagner mercenaries, it seemed, were less effective in battle: Wagner and pro-Assad forces were reported to have suffered up to 300 dead in a four-hour skirmish with American commandos in Khasham, eastern Syria, in February 2018 — thought to have been the first time Russian and US forces had clashed. The Americans were unhurt.

Not content with helping to destabilize Ukraine and Syria, Prigozhin turned his skills to waging asymmetrical warfare against the West. He set up an internet “troll farm” in St Petersburg that was accused of trying to magnify political divisions in America, encouraging voters to support Donald Trump in the 2016 US presidential election. This resulted in 2018 in America imposing sanctions on various Prigozhin companies and indicting him, along with several other Russians, for “meddling” in the election.

By then, Prigozhin had taken his army — and talent for disinformation — to Africa. In Sudan the organization advised the strongman Omar al-Bashir, who had been charged with multiple counts of genocide, on how to operate a social media campaign to discredit civilian protesters.

In 2019 Wagner deployed to Mozambique to help battle insurgents but quickly withdrew after humiliating losses. “Wagner frequently oversell their capabilities,” a Western defence source says. “Repressive regimes make Faustian bargains with them, using their nations’ natural wealth to buy security but finding themselves trapped with an expensive, unreliable and untrustworthy partner.”

A woman lays a flower wreath at the base of a monument in Bangui, the capital of the Central African Republic.

A Russian hearts and minds campaign in the Central African Republic has included screenings of Tourist, a Prigozhin propaganda film glorifying the “Wagner men”. A statue appeared in the capital, Bangui, showing Russian soldiers defending women and children. This is a travesty: besides multiple executions of civilians, the Wagner men are accused of widespread abuses against civilians. In May 2022 they stormed a maternity hospital in Bangui, raping health workers and new mothers.

Like other Russian oligarchs, Prigozhin dislikes outsiders delving into his affairs. Three Russian journalists investigating Wagner’s activities in the Central African Republic were murdered in 2018. Prigozhin has denied any involvement.

Korotkov, the Novaya Gazeta journalist, received a ram’s head and a funeral wreath at his office in Moscow after writing about Prigozhin — his newspaper has since had to suspend operations in Russia. British investigators, too, have been targeted.

Eliot Higgins, founder of the Bellingcat investigative news website, recalls his surprise at receiving a letter in 2021 from a British law firm representing Prigozhin. He was being sued for “defamation” over a series of articles linking the Russian to Wagner. “I thought, this is ridiculous,” Higgins tells me over the phone. “It seemed so obvious this was not a strong case.”

It has since emerged that the UK Treasury had approved a release of funds allowing the sanctioned Prigozhin to instruct Discreet Law and pay for business-class flights to St Petersburg so its lawyers could meet him — sanctions forbid him from setting foot in the UK. The case has intensified debate over the use of so-called Slapp rules, under which an oligarch wanting to suppress a story can threaten costly legal action unless the author agrees not to publish.

Discreet Law eventually ceased acting for Prigozhin, but not before Higgins had spent about $85,000 on his defense. “We need an independent inquiry to look into how this happened,” he says. “It’s an absurd situation and a clear abuse of the British legal system.”

Momentum may be gathering in the West to hold Prigozhin to account. “People here are beginning to understand more about figures such as Prigozhin,” Higgins says, adding that reports of discontent in the Wagner ranks spell trouble for him. “He sees Wagner as his way into power but a lot of his people are dying in Ukraine — it’s a risky strategy that could easily backfire. It’s all a bit Game of Thrones,” he says in a reference to the blood-drenched TV saga.

Wagner morale is low elsewhere too. “There are stories going around that the guys haven’t been paid in Mali and won’t leave barracks,” says my British mercenary contact. “They feel exposed because of the concentration of effort on Ukraine — accommodation and flights have suffered.”

Valery Vasilyevich Gerasimov, chief of the Russian Armed Forces and first deputy minister of defense.

Putin, meanwhile, seems to have sensed the threat posed by his “chef”. He recently appointed Valery Gerasimov, a Prigozhin enemy, as commander of the operation in Ukraine. Earlier this month the Kremlin gave the go-ahead for the Russian energy giant Gazprom to start its own private security force, which commentators fear could lead to yet another Wagner-like group – or one more loyal to Prigozhin’s enemies.

Whether or not he has overplayed his ambitions, Prigozhin, for his part, has embraced the sledgehammer as the chief symbol in his battle for power. A mass-produced version with a wooden shaft and iron head engraved with “Wagner” has gone on sale in shops across Russia, along with other Wagner “souvenirs” from keyrings to car stickers.

Weapon of mass destruction: a bloody sledgehammer.

Prigozhin said he was sending one to the EU parliament after it voted to brand Russia a state sponsor of terrorism in November last year. An internet video showed one stained with fake blood and packed in a violin case apparently ready to go. In another film he addresses “traitors” and wealthy Russians living abroad: “The Wagner sledgehammer will be waiting for you.” The sledgehammer, says a Russian friend who fled to the US, is “a message not just to us but anyone who stands in his way”. It is unlikely to encourage people to come home.

Matthew Campbell is a roving correspondent who, in more than 30 years at The Sunday Times of London, has covered numerous wars, natural disasters, and major political stories while serving as the paper’s bureau chief in Moscow in the early 1990s and, later, in Washington and Paris