It was the 3rd of November, 2020, and Renee Walk in Bristol looked like any other quiet residential street. Nothing out of place, no alarms raised. But behind the curtains, specialist officers were watching closely.
This wasn't a routine patrol, nor was it a lucky tip off. It was the result of weeks of surveillance, intelligence gathering, and strategic planning. Every movement had been monitored, every message quietly recorded.
And now they were ready to make their move. At the center of the operation was a single handover, a simple bag passed between two men. But it wasn't the shopping they were carrying.
Inside the bag, tightly wrapped in plastic, were 4 kg of high purity cocaine with an estimated street value of close to £400,000. Moments later, the officers moved. They forced entry into the property, arrested those inside, and seized the drugs.
In that moment, what had looked like just another weekday became the downfall of one of the most lucrative and sophisticated drug operations in the Southwest. This wasn't the result of luck. It was the final chapter in an investigation that had taken years to build, one that reached far beyond Bristol.
From encrypted phones to highowered vehicles, modified couriers to foreign suppliers, this was a business, not just a drug ring. And at the top of it all were Warren and Kelroy Allison, two brothers who ran the operation with precision, ambition, and absolute belief that they were untouchable. But what they didn't count on was Operation Yelm, a longunning datalled investigation by Wiltshire Police and the National Crime Agency.
It was designed to dismantle their network piece by piece and it worked. This is the real story of how greed, arrogance, and encrypted phones built an empire and how the very tools that made them feel invincible would eventually lead to their downfall. Warren and Kelroy Allison weren't your usual street dealers.
They weren't the type shouting orders on corners or flashing petty stacks on social media. Instead, the twins, one based in Swindon, the other in Trobridge, built a machine, quiet, deliberate, and welloiled. For over 4 years, it ran smoothly, moving more than 70 kg of cocaine across the Southwest with near military precision.
At the heart of it all was Warren Allison, the architect. He didn't just run the drugs, he ran the people. He had a clear structure, roles assigned, and risks calculated.
His brother, Kelroy, wasn't just involved. He was trusted. More than just family, he was the stabilizer in the background, handling day-to-day logistics, while Warren coordinated the bigger picture.
This wasn't a twoman show. Porsche Densley, Warren's romantic partner and crucially the gang's unofficial finance manager. She managed the money, collecting, delivering, and transferring funds on Warren's command.
It was Porsche who helped turn the operation from a cash heavy street trade into something resembling a fully operational business. Clean on the surface, ruthless underneath. Then there was Richard Cowell, a 57year-old from Swindon who became one of their most vital assets.
A quiet, seemingly unremarkable man who drove a specially modified vehicle complete with a hidden compartment designed to move class A drugs and large sums of cash across county lines without detection. But as the business grew, so did the cast. Anthony Burke, Warren and Kellroyy's cousin, became part of the inner network.
He was on the receiving end of a key 4 kilo drop in Bristol, the delivery that eventually brought the entire empire crashing down. His flat in Ronain Walk became the scene of a pivotal arrest in November 2020. Behind the scenes, the gang leaned on international supply.
That's where Leian Hawkhar and Cheetah Pisha, both Albanian nationals, entered the picture. They supplied large quantities of high purity cocaine into the Southwest pipeline. Their links extended beyond just Wiltshire.
Their role made it clear the Allison's weren't just local dealers, but part of a larger European supply chain. And finally, Enid Alico, the gang's tech conduit. He provided a Sky ECC encrypted phone and acted as the direct line between the Albanian syndicate and the Allisonens after the November sting.
A digital middleman who stepped in when the heat was rising. Their network expanded and with the rise came comfort. High value cars, lavish purchases.
Warren was seen driving a Lamborghini Huracan alongside a Mercedes C63 AMG and an Audi RS6. These weren't subtle, but by then they didn't care. Apart from this, together these eight people formed a drug empire, structured like a business, moving weight like a wholesaler, protected by encrypted devices, burner phones, and a growing sense of invincibility.
But behind the confidence, behind the tech, the cars, and the cash, Wiltshire police were watching. What started with whispers and suspicion would soon become Operation Yelm. And the cracks were already starting to show.
For years, encrypted phones gave Britain's criminal elite the upper hand. For the Allison brothers, they were the shield that made their empire possible. Secure devices like Encroat and later Sky ECC allowed them to operate without fear of interception until it all came undone.
Each member of the crew had a role to play and with encrypted devices in hand, communication was tight and traceable only by handle names. Warren Allison used the alias legal master. Richard Cowell operated as South Kangaroo.
These weren't usernames for show. They were lifelines. Through these devices, drugs were sourced, prices negotiated, cash collections arranged, and police movements anticipated.
The brothers operated with a digital arrogance, certain that their systems were impenetrable. And for a time, they were right. Encroat was considered uncrackable.
Criminals up and down the UK used it freely to conduct deals, plan drops, and flex untouchable status until French law enforcement brought the whole network down in June 2020. The fallout was immediate and farreaching. Across Europe, hundreds of arrests were made.
In Wiltshire, panic quietly rippled through encrypted devices, and behind the curtain, Wiltshire's serious organized crime unit had already been watching. From the outside, the Allison's business still looked seamless. But behind the scenes, Operation Yelm had begun linking devices, building timelines, and uncovering encrypted chatter that would become devastating evidence.
It was around this time that Enid Alico became more deeply involved. With Encroat compromised, the gang switched to Sky ECC, a newer, even more expensive encrypted platform. Alico sourced the hardware, managed connections, and kept the gang online.
But the trust in tech had already taken a knock. By late 2020, the Allison Brothers Empire looked solid on the surface. The drugs kept flowing, the money kept moving, and encrypted phones gave the illusion of safety.
But behind the curtain, law enforcement was tightening the net. Surveillance teams had eyes on every key player, and Operation Yelm had already mapped the operation from top to bottom. Then came the setup that would bring everything crashing down.
Tuesday, November 3rd. Renain Walk, Bristol. A 4 kilo shipment of high purity cocaine was scheduled for delivery.
The deal was arranged by Warren Allison, who had now stepped into the role of broker. He wasn't just buying or selling. He was orchestrating the transfer of product from Albanian suppliers directly to his own cousin, Anthony Burke.
On the supplier side were Leian Hawkhar and Pieta Pisha, two Albanian nationals who delivered the drugs straight to Burke's flat, tightly packed and carried, of all things, in a bag for life. What none of them realized was that undercover officers were watching the entire thing unfold. Moments after the exchange, police moved in.
They forced entry into the address, arrested Anthony Burke, and seized the cocaine, 4 kilos with an estimated street value of between £320,000 and £400,000. Within hours, the panic began. Both Hawker and Pisha fled the country in a desperate attempt to escape prosecution.
But it was too late. The authorities already had enough evidence in the form of surveillance footage, device data, and intercepted encrypted messages left little room for doubt. The bust wasn't just a sting.
It was a keystone moment. A live captured handover with hard evidence that linked the Allison brothers, their suppliers, their courier, and their logistics network in one tight chain of command. And for the team behind Operation Yelm, it confirmed what they already suspected.
This wasn't a regional crew pushing a few ounces. This was a full-scale international trafficking operation built on encrypted networks, custom vehicles, and a hierarchy that stretched across borders. The gang had always believed they were one step ahead.
But on that November afternoon in Bristol, they found out just how closely they'd been watched. So, what was the Operation Yelm actually? It didn't start with the Bristol bust.
It didn't even start with the encrypted phones. Operation Yelm had been quietly ticking away behind the scenes for months, launched after local intelligence flagged unusual movement and suspected drug activity around Swindon and Trowbridge. From there, Wiltshire police began to piece together something far more complex.
The case was led by Wiltshire's serious organized crime unit alongside NCA. Their goal wasn't just to make a few arrests. They wanted the full picture.
Every supplier, every courier, every transaction, and to get that, they had to go deep. Surveillance became routine. Properties were watched.
Vehicles were tracked. Phone data was quietly collected and stored. Then came the collapse of Encroat in mid 2020.
Thousands of encrypted conversations were suddenly accessible to police, including those linked to the Allison Brothers. For Warren and Kelroy, it marked the beginning of the end. A key breakthrough came in 2021 when officers from the Chippenham neighborhood policing team executed a warrant at Kelroy Allison's home in Hilpertton.
Inside, they recovered multiple mobile phones. Forensic analysis of those devices uncovered years of drug ledgers, messages, and contacts. Solid evidence linking him to cocaine trafficking dating all the way back to 2008 January 2016.
Meanwhile, data pulled from Cowell's and Warren's Encro chat device helped investigators draw direct lines between encrypted instructions and realworld drug movements. Timelines were matched, phone reports synchronized, and geographic data pulled from devices. The evidence was no longer circumstantial.
It was concrete. Richard Cowell was arrested at his home in Swindon. His modified vehicle, complete with the purpose-built concealment compartment, was seized during the arrest.
Officers recovered his encrypted device and confirmed his courier role in the wider network. Warren Allison was arrested as the ring leader. His devices and finances were seized, including a Lamborghini Huracan, Mercedes C63 AMG, and Audi RS6, all purchased with laundered cash.
Porsia Densley was arrested shortly after. The National Crime Agency, NCA, also played a key role. Their digital specialists helped extract and interpret the data stored on Sky ECC devices while analysts tied communication patterns between Albanian suppliers, the Allisonens and Enid Alico.
Alico was arrested for supplying encrypted communication devices and facilitating contact between the UK operation and Albanian suppliers. Ledian Hawkar and Pieta Pisha, the Albanian nationals who supplied the cocaine for that drop, fled the UK soon after the arrest, but warrants were issued swiftly and both men were tracked down and arrested abroad. They were later extradited back to the UK to face sentencing.
Altogether, Operation Yelm became a textbook investigation built on patience, community intelligence, modern tech, and old school surveillance. It dismantled the Allison Empire from top to bottom. And when the time came to bring the case to court, police didn't walk in with accusations.
They walked in with thousands of pages of evidence, years of digital trails, physical seizures, and surveillance logs that told the story in full. The trial took place at Winchester Crown Court and ran for 12 weeks. Prosecutors laid out a detailed case built on encrypted messages, surveillance, financial trails, and forensic phone analysis.
The evidence painted a clear picture. This was no small-time operation. It was a long-standing structured conspiracy to supply vast amounts of class A drugs across the Southwest.
Warren and Kelroy Allison along with Richard Cowell, Porsche Densley, and Anthony Burke, all denied the charges. Their defense claimed the messages referred not to cocaine, but to counterfeit clothing. But the jury wasn't convinced.
Every key element presented by the prosecution, communications on Encroat and Sky ECC, the vehicle concealments, the ledgers found on Kelroyy's phone, and seized 4 kg of cocaine, left little doubt about what was really going on. The weight of evidence was simply too strong to ignore. While five of the accused stood trial and were found guilty, three others, Ladyian Hawker, Peter Pisha, and Enid Alico, had already entered guilty prior to the hearings.
On the 6th of February, 2024, sentencing was delivered. Warren Allison was handed 23 years in prison. His brother Kelroy received 16 and a half.
Cowell was jailed for 9 years and Densley for eight. Anthony Burke also received 8 years. Huxar was sentenced to 7 years and 4 months, Pisha to 6 years and 8 months and Aliko to 4 years.
A total of 82 years of prison time was handed down, bringing one of Wiltshire's largest drug cases to a decisive end. Let us know your thoughts on this case in the comments. And if you found it as shocking as we did, do us a favor.
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