Crouching in the darkness, cupping cigarettes in their hands to avoid being seen by snipers, Robert Daw and Rae Lewis-Ayling waited for the signal to run. Everything was going to plan.

The razor wire was no more than 100 metres ahead – an easy dash for two fit 20-somethings in workman's boots. Up in the distance, they could just about make out the glow of a sentry post and the silhouettes of two guards smoking behind a window. "For you it's OK," whispered one of the heavily-accented Kurdish revolutionaries who'd agreed to smuggle them into Syria in the dead of night. "If guards come, they put you in jail. Us, they kill."

It was the 1st of August, 2017, and the two young Brits were as close as they’d ever been to realising their dream. They were finally being smuggled into Rojava, the Kurdish region of northern Syria where the People’s Protection Units (YPG) had been waging war with Isis since 2011. They had waited nine days in Iraq for the dark moon to rise – giving them the safest possible passage across the border. And now, finally, they were there. Almost.

Without warning, a shout in a language they didn't understand tore through the velvet darkness. The click-clacks of cocking weapons immediately followed, and a group of 30-odd Peshmerga border police materialised, all yelling at them to lie on the ground. "In that moment, I realised the dream was over," says Rae.

He had no idea of the nightmare that was about to begin.

WATCH:

Rae, 25, is a railway worker from North Wales. Rob, 21, is a security guard from Preston. Both are dyed-red socialists, having met at a Labour Party members' gathering in their teens, and best friends. I meet them in a pub in London's New Cross in early September, 2017. Neither are particularly tall or tough-looking. Actually, they're scrawny and pale, with patchy facial hair and bitten fingernails: certainly not, by the looks of them, the sorts to take up arms on the most violent and lawless battleground on Earth. "We're not – that’s not why we went," says Rob. "We went to help the revolution."

Northern Syria is in the midst of radical transformation. Inspired by the ideology of Abdullah Öcalan, the imprisoned leader of the outlawed Kurdistan Workers' Party (PKK) in Turkey, and triggered by the "Arab Spring" of 2011, people are organising themselves into grassroots assemblies and co-operatives, declaring their autonomy from the state and their wish for real democracy. Anti-capitalist, Marxist and feminist ideas are flourishing, including a system of co-presidentship whereby a man and a woman share power at every level. In the YPG, officers are elected by troops, and men and women fight side-by-side.

The experiment has proved seductive to leftists across the world. Inspired by the International Brigades of the Spanish Civil War, dozens of far-left Westerners have flocked to Rojava since a first wave formed the International Freedom Battalion (IFB) in June of 2015 in response to what they called a "bloodbath" in the Middle East. "Ultimately, [Syria’s Kurds] want to destroy the patriarchal structure that they say oppresses women, and rebuild an equal society where everyone has a say, regardless of race or gender," says Rob. "All that in the heart of the Middle East! From the moment I heard about Rojava, I had to be a part of it."

Syrian and Iraqi Kurds, however, don't exactly see eye-to-eye. "The US-influenced Kurdish Regional Government (KRG) of northern Iraq is a capitalist authority and at odds with what is happening in Syria," says Rae. "Woe betide anyone caught trying to cross."

READ:

"You Isis," the soldiers yelled. "We kill Isis." They handcuffed and blindfolded the two men and held guns to their heads, threatening to pull the trigger. "My legs were shaking with fear," says Rob. "I honestly thought we were going to die. But in that moment, what could we do? I just closed my eyes and waited for it."

They didn’t shoot. In hindsight, Rob and Rae say these were barely soldiers at all, but low-ranking, overexcited teenage border guards.

Over the next two days the two young men were bounced between various rural police stations for questioning. They say, in that time, they were not once offered a lawyer, let alone a phone call. "We told them the truth," says Rob. "We said we were humanitarian workers, not there to fight but to help Syria's Kurds build a better society."

Then, on the 3rd of August, they arrived in Erbil, the capital of Iraqi Kurdistan, where they were frogmarched into a holding cell in the city’s General Security Directorate – an imposing American-built compound where Iraqi Kurdistan’s worst criminals are held. "Everyone stopped what they were doing and looked at us," says Rae. "We didn’t know if we should just go and sit in a corner and hope for the best, or attack the biggest guy in the cell, like we’d read you're supposed to do in prison."

They did neither. Because, at that moment, a Spaniard, a Brazilian and a Frenchman approached them, shook their hands warmly and told them, if they stuck with them, they’d live. It was then that the Brazilian whispered, "Welcome to Hell."

They say the cell was 5m x 13m and occupied by 100 men. At night, the only way to sleep was on their sides, squished together like sardines. "They never once turned off the halogen lights," says Rae. "We didn't see darkness for more than a month. That’s what fucked with everyone’s minds the most."

Inmates ranged from rapists and drug dealers to Kurdish revolutionaries and a handful of other Westerners who’d fought with Rojava’s YPG until they were arrested trying to get home. Order inside the cell was kept not by the guards, but by an inmate named Zrian, a stocky ex-Peshmerga soldier and chief snitch. "Every single thing that happened, he would tell the guards," says Rae. "He was mates with the rapists and the most powerful man in the cell. Like, at 1PM every day he would make everyone take a nap for two hours. It was a power thing."

Robert in Kurdistan

Days coalesced into weeks, and Rae and Rob began to wonder if they’d ever get home. "We had no idea if our families even knew we were alive, let alone where we were," says Rae. "And this was not a place we wanted to stay."

The guards, they say, were violent and sadistic, dishing out beatings for transgressions as small as laughing in their presence. Not Rae or Rob, though. "I later learned they’d been told to leave us alone because we were classed as political prisoners, not fighters," says Rae. "The others weren’t so lucky."

The constant light, fear of beatings and boredom caused some men to lose their minds. "There was so little to do that there were fights over who’d mop the floor," says Rob. "That said, it did mean the cell was always spotless."

Two weeks in, two Spaniards – more captured YPG fighters – were dragged in, bloodied and beaten. One was in such bad shape he seemed, essentially, in a coma, possibly after a stroke. "He was so dehydrated that when you pinched his skin it didn’t snap back like yours or mine would," says Rae.

They implored the guards to take him to hospital, but were told it wasn't their problem. "The only reason the Spaniard is still alive is because a Kurdish inmate called Omut – the guy had completely lost his mind – attacked him out of nowhere with a kettle, smashing open his skull," says Rob. "This made him the guards' problem, because the injury happened on their watch." They took the man for medical treatment.

On another occasion, they say they awoke to the chilling sound of a 14-year-old boy being gang-raped. "I later learned he was only in for possessing cannabis," says Rae. "But what could we do? The rapists were Zrian's mates. If we’d stepped in they’d have turned on us."

Inmates were allowed one hour a day to walk about in a small yard with a roof, and to use cubicle toilets with actual toilet paper (the one in the corner of the cell had no such luxury). In that time, three men tried to commit suicide by tearing strips of blanket with which to ligature themselves. "I had to save one of them by climbing over a toilet door after he’d locked himself in and started screaming," says Rob. "I guess he’d decided he didn’t want to do it after all."

The food, surprisingly, was good: mostly bread, yoghurt, goat or chicken, plus rice or boiled potatoes cut into soggy fingers. There were moments of levity, too. Like the chain-smoking 70-year-old former Mujahideen-turned-Taliban-fighter-turned-Al-Qaeda-operative who constantly gave out cigarettes and taught Rae how to play chess.

Then there were the revolutionary Kurds who would sit in circles and sing old Kurdish songs. "In the end, we joined in teaching them old British socialist songs, like 'The Internationale' and Billy Bragg, and they loved it," laughs Rob. "'The Power of the Union' was a banger for us."

Rob even had his 21st birthday in the cell, and some of the other European inmates managed to get a cake smuggled in. "I've no idea how they did it, but it was one of the most touching moments of my life," says Rob.

By about the middle of August, rumours began circulating that a new inmate from Germany was to join them. "We were quite excited to meet a new Westerner," says Rae. "Someone who hopefully spoke English."

But the man who lumbered into the cell was not what they expected. Thick-set with muscles as bristling as the beard engulfing his face, this man – it was quite obvious – could only have come from one place: The Islamic State of Iraq and al-Sham. Still, Rae, who speaks a little German, introduced himself. The man responded in a way neither could have imagined.

"Sup, nigga?" he grinned in near-perfect English, before shaking their hands like an LA street gangster. "He was clearly nervous," says Rae, "but he seemed to warm to us immediately because we were British. I mean, he spoke like a fucking weirdo, but at least he did it in a language we could understand."

The man's name was Deniz, a Turkish-German national from Frankfurt. The 25-year-old had been seized, he would later reveal, trying to flee the jihadi life with his favourite wife. "He was one of the few men who spoke fluent English as well as Arabic, and translated for us with the guards," says Rob. "You could see behind his mask that he was a fucking awful human being: he kept slaves, had more than one wife and would boast about how he tortured Kurdish civilians for fun. But surreally, in the moments we forgot about all that, he was likeable. I remember one night when Deniz woke me and Rae up by singing 'Where Is the Love' by the Black-Eyed Peas at the top of his voice."

Deniz (whose surname we have omitted, as he is currently on trial in northern Iraq) wasn't what they imagined an Isis radical to be like. He had the Capricorn star sign tattooed on his neck and would talk excitedly about his love of Mars bars and his favourite movies, Inception and 2 Fast 2 Furious.

"He was like two people," says Rob. "Almost in the same breath he’d tell us how wonderful it was that the only instrument permitted in the Islamic caliphate is a drum during certain verses of the Qur'an, before going on to say how much he loved American gangster rap. He was obsessed with DMX and 50 Cent. Deniz was one very confused dude."

Within a few days, Deniz began spilling his life story. He claimed he'd spent much of his twenties running a muscle gym in Frankfurt, where he'd become addicted to steroids, until he fell in with a Mexican street gang in the city and discovered cocaine. "Then, one day, he decided to convert to Islam, marry a Muslim woman and travel to Iraq to join Islamic State," says Rob.

Yet, of all the chats they had with Deniz, there was one that stood out in particular. "I don't know much about Islam, and wanted to find out more about his version of it," says Rob.

The conversation went like this:

Rob: Deniz, do you read the Qur'an literally, then?

Deniz: No, we take the word of scholars on YouTube.

Rob: Where are these scholars based?

Deniz: The UK. All of the videos on YouTube we watch in IS are from Islamic scholars living in the UK. All of them.

"I was like, 'Jesus, fuck,'" says Rob. "It blew my mind. I think he was a very lost and lonely guy searching for an identity – something with which to say, 'This is me.' He very briefly found that in Islamic State. Then he got scared."

At first, Deniz said he'd fled after becoming disillusioned with the war crimes he'd seen. But as weeks passed, he began to admit committing such crimes himself. "In the end, he said he'd left because he didn't want to die," says Rae. "He was scared of drones. Dying, he said, wasn't really his thing."

VICE contacted Deniz's father to verify Rob and Rae's claims. In a phone conversation he wouldn't comment on the allegation that his son had joined IS, citing his ongoing trial, but did confirm that Deniz and his wife had surrendered to Peshmerga forces in northern Iraq. He also denied that Deniz had taken steroids or cocaine; that he was involved with gangs; that he once liked rap music; and that he has a Capricorn tattoo.

WATCH:

Soon after Deniz arrived, Rae and Rob were finally allowed a phone call. So they rang the only number they knew by heart: Rae's mum. "She was our lifeline," says Rae. "She rang the British Foreign Office, who sent the British Consul General from the consulate in Erbil to see us. He told us to hang on a couple more weeks while he worked on our release."

After 30 days, they were allowed to use the phone again. "Rae's mum told us we’d been pardoned but would have to wait another ten days, until the end of Eid."

Those days passed like all the others until, on the 10th of September, the Consul General returned. "He said the KDP weren’t renewing our visas, so technically we were in the country illegally. He said we’d have to pay $340 in visa fines, get our stamps and get out."

Twenty-four hours later, they were on a plane to Heathrow.

A spokesperson from the UK Foreign and Commonwealth Office would not comment on the details of Rob and Rae's case, but said: "We provided consular assistance to two British nationals detained in Iraq from August to September. Both of the individuals have now returned to the UK."

The pair never found out what happened to their guides after the arrest on the 1st of August. "I think they’re probably dead," says Rob. "But we'll never know."

Now safely home, Rae and Rob have found jobs – Rob on the railways and Rae in construction. They have moved into a flat together in London, and Rae is engaged.

They still think of the chess-playing Mujahedeen and the Western YPG fighters. Every now and then, even Deniz enters their minds.

Do they feel traumatised by the ordeal? "I do still wake up some nights and think I’m still in that cell," says Rob. "I get a shudder every time I hear someone jangling their keys," adds Rae. But, on the whole, the pair seem surprisingly chipper given the experience.

When I ask if they regret what they did, Rob’s eyes flash with defiance. "Not for a fucking second. If I could go again, I would. My only regret is not getting into Rojava. I know we could have done good things over there. Even if I just helped build a house, someone who needed it would have got that house for free. That would’ve been enough for me."

Rae chips in: "If anything, it's taught me how scared the reactionary forces in that region are of the Rojava revolution. They’re willing to lock up socialists like us in a prison where we very well could have died."

What if they had died? Rob laughs. "Many people have died in the name of socialism before. I certainly don’t want to die, but if you're going to kill me then the flag stays red. Do you know 'The Red Flag', the Labour Party anthem?"

"Maybe not all the lyrics," I mumble.