Brad’s* doctor had never heard of Xanax.

The 17-year-old sat in his GP’s office in August 2016, explaining to him everything he knew about the drug.

When he and his friends started experimenting with an illegal, counterfeit version of Pfizer-brand Xanax at the beginning of 2016, it was just a fun thing to do at parties – or, occasionally, a way to come down after a heavy weekend.

Eight months on, he had a four-pills-a-day habit and felt he was “losing it”. He was apathetic – and occasionally violent. He could feel his personality changing.

Brad decided to quit cold turkey. Withdrawal from benzodiazepines – the family of drugs to which Xanax belongs – can be life-threatening, so he knew it was going to be difficult. But he was still unprepared for his first seizure, a week and a half later.

That was when he decided to tell his mum, and that’s how he ended up in front of his GP in Kent, trying to explain how he’d managed to get hooked on an anti-anxiety medication that was prescribed just 14 times in 2016 according to NHS England.

“My GP Googled it,” says Brad. “Every medical professional I’ve seen about my seizures hasn’t known what Xanax is.”

Officially, Xanax barely exists in the UK. In America, it’s the third most popular psychiatric drug according to one peer-reviewed study – a modern lotus plant with cult status among celebrities and a notoriety made worse by its implication in the recent death of rapper Lil Peep. But in the UK, it’s usually only available with a private prescription.

Even so, over the last three years many different parts of the UK have reported the mass-hospitalisation of schoolchildren in fake Xanax-related incidents. These include six London schoolgirls who allegedly took it in school in February; “up to 20” young people in Wiltshire in May 2017; and five Sidmouth teenagers in June 2016. NHS Grampian and Police Scotland issued warnings in January 2018 after alprazolam – the generic name for Xanax – was implicated in more than 20 deaths.

The Red Devil: a limited-edition 5mg counterfeit Xanax pill, introduced in 2016 in what has been widely interpreted as a marketing stunt.

Xanax's scarcity in the UK means that for illicit dealers, getting regular supplies of the drug is difficult. So in late 2015 some innovative dealers decided to take a new approach: they began pressing their own pills in the UK using powder imported from China. This enabled them to produce huge quantities of the drug at extremely low cost.

Border Force data obtained by BBC Three provides a glimpse of the scale of the operation – and the struggle of the authorities to contain it – for the first time.

In January 2017, law enforcement successfully intercepted a huge shipment of alprazolam powder. The three seizures amounted to more than 50kg – enough to press more than 25 million counterfeit Xanax pills containing 2mg alprazolam each. It suggested that an enormous commercial operation was underway: the largest in UK dark net history.

It would be the first and last time they intercepted such a quantity, however. Between January 2015 and March 2017, they only caught another 3kg of powder. But they did encounter huge quantities of pills: 183 seizures altogether, amounting to 860,989 counterfeit pills.

Now the details behind the surge of fake Xanax on Britain’s streets can be revealed for the first time. Transaction data from dark net markets AlphaBay and Hansa analysed by BBC Three show that over a period of 21 months from 2015 to 2017, more than 1.5m counterfeit Xanax pills flooded Britain’s illegal drugs market. They were sold online, often distributed in 'k-packs' of 1,000 pills to dealers – working out at 35p per pill –then resold on the streets for £1-5 a pill.

The market was monopolised by one producer and one supplier, and a close circle of assistants. Their main product was a distinctive white counterfeit Xanax pill, but they boosted their profile with a bold marketing stunt: a limited run of ‘Red Xanax’ – at its time the most potent benzodiazepine on the market. Their revenue ultimately ran into millions – and they achieved it all in plain sight, leaving a brazen and extensive online trail.

Then in summer 2017, police intervened. They made their first arrests in June,seizing more than 250,000 tablets in the process. Further arrests were made in October – this time for drug production offences.

The arrests effectively ended the fake Xanax rush. But the disappearance of the drug created a new problem: dozens of benzodiazepine-addicted teenagers,like Brad, who were taking the drug on a regular basis, and now faced an uncertain supply.

There have also been deaths. One was a friend of Brad’s: a 19-year-old who died earlier this year after ingesting an unknown combination of drugs. Brad’s friendship group had been mixing fake Xanax with other drugs that act as depressants, such as ketamine – the combination of which can be deadly.

“We’d had fun with uppers like MDMA but once we discovered downers and ketamine that was all we did,” says Brad.

Teenage drug use is no longer going down, as the Home Office once insisted; it has risen overall since 2013 – and fake Xanax is one of the most hyped drugs around.

WEDINOS is the UK’s publicly funded drug-monitoring service. In its 2016-17 top ten of the most commonly detected New Psychoactive Substances, alprazolam ranked third.

In the wake of such demand, there is no shortage of dealers working to restore a consistent and reliable production line so they can capitalise on the appetite of drug users. The pressure on authorities to put the dealers behind bars is increasing.

As months have passed with no charges yet brought, however, concern is rising that the police may have allowed the biggest dealers in UK dark net history to slip through their fingers.

Registering a business on AlphaBay – one of the world’s largest drugs markets until it was shut down by the FBI on 20 July 2017 – was not unlike setting up a business on eBay. Vendors registered a username and email address, and paid a bond (usually $200). Hulked Benzo Boss (HBB) did this on 15 September 2015, and set to work posting listings and accumulating feedback.

HBB offered genuine – albeit diverted – medication: boxed, blister-packed pharmaceuticals, from approved laboratories produced according to strict quality controls. It was the kind that would be available at any UK pharmacy on prescription – with a few crucial differences: HBB was not a pharmacist, the buyer didn’t need a prescription, and the sale of the medicine was illegal.

HBB was not alone. Several UK-based retailers on AlphaBay were doing the same thing at the same time: offering boxes of prescription-only pharmaceutical medication like the opiate codeine, and the sleeping pill zopiclone. Later, there came new product lines: ‘blueberry’ viagra, and opioids dihydrocodeine and tramadol. Like many other retailers, he also sold diazepam, which is very similar in its effects to alprazolam.

When HBB introduced counterfeit Xanax to the market, it wasn’t dramatically different to what was already available. By combining ruthless efficiency with aggressive marketing, however, he would rapidly become one of the most prolific and profitable drug dealers on the dark net.

The AlphaBay forum was somewhere drug dealers and users of all description came together to talk business, gossip and call out scammers.

It was also a place full of fake identities and promises that were never delivered. When HBB teased his new product on 22 November 2015, he was full of optimism: “We will hopefully soon be getting the best Xanax you'll ever try,” he wrote. But reaction was lukewarm.

On 31 December, HBB made his first listing: 10 x 2mg bars for about £12 including postage. A week later, he listed 100 for £85, and promised that bulk listings of up to 500 pills would follow. In all of his listings, he described the pills as “Pfizer Xanax”. In the weeks that followed, he would admit they were actually fakes, pressed using alprazolam imported from overseas.

“You’re never in a million years going to [get] your hands on 100k legit Xanax bars, or any other branded alprazolam,” he wrote on AlphaBay, by way of justification, in July 2016.

These were what HBB described as ‘Pharmaceutical Grade’ – although they were subject to none of the pharmaceutical industry's rigorous checks and balances. They were machine-mixed and pressed so as to appear identical to Pfizer’s distinctive oblong pill, indented with the letters X-A-N-A-X. They were manufactured by a supplier called UKBenzos (UKB).

UKB was a mysterious figure on dark net forums. He emerged on AlphaBay in early 2015, selling a very similar range of drugs to HBB on various dark net markets – also with favourable reviews.

At some point in 2015, UKB decided to start pressing alprazolam into pills himself. The drug was available by the kilo from Chinese laboratories which had already forged links with the UK thanks to the trade in legal highs established years previously.

Domestically, though, there seemed to be little demand for Xanax. HBB decided to introduce new incentives. On a post in AlphaBay forums titled, “So it’s a Price War people want, eh?..”, he slashed his prices. He would be selling packs of 1000 fake Xanax for £350.

HBB’s attentiveness ensured the business kept ticking over nicely. He always seemed to be online to give feedback, and issues were dealt with quickly.

Word began to get around. The pills may have been counterfeit, but forum users posted reviews praising their quality – and the customer service was excellent.

11 March 2016 was a typical day: HBB’s AlphaBay account registered 21 sales, three of them for 50 bars of counterfeit Xanax. If HBB wanted to make more money, though, he needed to get street dealers buying his product and ‘flipping’ it, or selling it on. He needed to start selling packs of 1,000 – and more.

HBB had promised a limitless supply of pills, so it came as a surprise to some that in mid-April, he claimed to have sold out. By now, he had built up enough of a following to pique the curiosity of dark net market regulars. Posts started racking up on AlphaBay and other forums asking when his bars would be back in stock. Demand was rising.

A few weeks later, HBB returned. “UK Xanax scene is back baby!” he wrote on 10 May. “Listings back up, cheaper than previously as well. We sold them at an unbelievable speed last time, and fully anticipate the same thing this time, so the stock is stupidly high! New presses coming soon too!”

This “stupidly high” stock was a major draw. People buying drugs from forums frequently faced shortages and delays. Reliability was highly prized.

Positive reviews began flooding the forums. Delivery times via the postal service were good – one or two days, according to many users. And the appearance of the parcels themselves was “Nothing to worry about at all, blends in to all regular mail and no rattling around,” according to one review.

“Stunning bars, just like previous batch. On point with dosage,” wrote another.

HBB now had a loyal customer base. He had offered better service than his competitors with a faster delivery, a consistently high-quality product and regular communication. HBB and UKB had created the UK fake Xanax market. But they wanted more.

On 26 May 2016, HBB introduced a new drug: the R/666 Red Devil. It was an enormously potent counterfeit Xanax pill that had been dyed blood red.

One single Red Devil contained more than 5mg of alprazolam: the equivalent of two-and-a-half of HBB's regular white 2mg pills. It was stronger than any single benzodiazepine available on the international illicit market at the time. If a person with zero tolerance took it, it would likely send them to sleep for hours. Combined with other depressants – such as alcohol or opioids – it could kill.

The thread on AlphaBay forum received 111 replies from interested parties.

“We’ve also lowered the minimum International order to 25 bars for 48 hours only!" wrote HBB. "So if you want to sample the devil, they're waiting...”

A single Red Devil contained more alprazolam than any individual should consume in a day, according to Professor Colin Drummond, a member of the Faculty of Addictions from the Royal College of Psychiatrists.

“After just a few weeks of taking benzodiazepines, you develop dependence so that your tolerance for the drug increases and you start taking larger and larger doses," he told BBC Three.

"When you stop taking the benzodiazepines you end up with withdrawal symptoms, which give you things like anxiety, panic attacks [and] sometimes hallucinations.

“The longer it goes on, and the higher the dose, the worse it becomes.”

Red Devils were a way for HBB and UKB to demonstrate their production skill and draw the attention of the world. In the following weeks, orders snowballed.

UKB and HBB had been offering “K-packs” of 1,000 pills before, but now HBB started really pushing these bulk orders – explaining to dealers how to ‘flip’ them and turn a profit.

“£2-3 a bar is not uncommon, and I know of people who sell 3 for £10,” he wrote on 11 June.

A K-pack cost £350, meaning a smart dealer could easily triple their investment.

Not everyone was convinced, however. “I can’t even sell Xanax where I am,” replied one user. “No one’s heard of it. Brought 200 from UKBenzos, was given 200-300 more free, gave 30-50 out as testers.

“Now left with under 200 and a nasty habit.”

HBB was unfazed.“[fake] Xanax is growing massively in the UK atm,” he wrote in the same thread, “and you’ll see usage surpass diazepam by the end of the year.”

Diazepam is a relatively commonly abused prescription benzodiazepine. Genuine diazepam is much easier to obtain illicitly than alprazolam because it is widely prescribed – and huge quantities are diverted to the black market. There were 5.2m prescriptions for diazepam in 2016 according to NHS England. But HBB seemed to understand something about the appeal of Xanax that others vendors didn’t.

In recent years, Xanax has infiltrated US pop culture in a way few other drugs have. It’s a pill that artists like Future rap about, and everyone from Justin Bieber to Tiger Woods seems to have abused. ‘Flexing’ it on Instagram – in other words, showing it off in pictures – signalled to other teens that you were in on it.

One of the earliest high-profile fake Xanax scares in the UK happened in Salisbury in May 2017.

“A lot of younger girls probably around 14-16 were taking it quite frequently,” Rob, a 16-year-old from the area, tells BBC Three.

Initial reports of “up to 20” hospitalisations were probably exaggerated, he says. But teenagers in the area had been taking fake Xanax for several months, and it was widespread enough for the local police and schools to issue warnings to parents.

Suddenly fake Xanax was all over the news. Mainstream publicity was good for business, but it also risked attracting the attention of the authorities.

Pfizer Global Security is the arm of Pfizer devoted to investigating counterfeit medication. It has offices in the UK, US and China.

Its UK arm includes former National Crime Agency and Metropolitan Police officers, and its facilities include a lab at Sandwich for analysing drug samples.

BBC Three spoke to dark net vendors and forum users who claimed that Pfizer Global Security initiated an investigation into the sale of counterfeit Xanax in the UK, handing over what they uncovered to police.

Pfizer declined to confirm their involvement to the BBC, stating, “It would be inappropriate for us to comment on a police investigation”.

They did, however, confirm they work "with law enforcement agencies to successfully prosecute counterfeiters".

Police gave BBC Three a similar statement: “We work closely with companies and other agencies to identify counterfeit products and take them off the streets.”

On 14 March 2017, HBB announced he was looking for two resellers to take over operations: one for domestic purchases and one international.

This was no small feat. HBB claimed that he was sending pills to places as far flung as Australia, Ukraine and Saudi Arabia – and more than 5000 per day to North America.

He posted the job ads on an internet forum in public view:

“You must already be a well-established vendor, and capable of dealing with up to 100 orders (We peaked at 223 over one weekend). You will get better rates than retail customers, standard. Prices to be set by yourselves, but you will be able to keep them close to ours, with the addition of being the Official HBB reseller. If you think you fit the bill, message us from your VENDOR account so we know you have one,” he wrote.

HBB wrote that he was getting “too old” for the game. “Just taking a back seat,” he wrote in April. But he had also made a lot of money.

"My revenue on AB [AlphaBay] is over £1m," he wrote to another user in May.

A couple of weeks later, he appeared to have completed the domestic handover to a vendor calling himself ‘Imperial Stormtrooper’.

But the net was already closing on the UK fake Xanax market.

A special division of Thames Valley police called the South East and Regional Organised Crime Unit (SEROCU) had opened a file on “the supply of Alprazolam which was predominately being sold as counterfeit Xanax”.

On 13 June 2017, they made their first arrests: a 30-year-old male and a 27-year-old female, arrested in Hampshire for the offences of supplying a controlled drug of Class C and Money Laundering. Both were released under investigation. According to a statement released to BBC Three, they also seized over 250,000 tablets which consisted of counterfeit Xanax, Sandoz GG249, Greenstone G3722 and Qualitest Pharmaceuticals Inc V2090.

There were only two vendors openly selling these quantities and varieties of medication on the darknet at the time: HBB and UKB.

“With a heavy heart I have to report HBB is currently missing,” wrote Imperial Stormtrooper on June 22.

The rumour, according to associates of HBB – although one that has never been confirmed by police – was that he had been busted.

“Sadly for you lot I will be out of bars within a couple of days and then there may not be any more from me unless HBB reappears with a reasonable explanation or ukbenzos reaches out to me,” continued Imperial Stormtrooper.

If HBB had been caught, police might have been able to identify UKB and Imperial Stormtrooper - unless they had been extremely careful to minimise contact and encrypt communications.

On 5 October 2017, a second series of arrests was made – this time for the production of drugs.

“Three men were arrested on the 5 October 2017: a 30-year-old and 25-year-old from Bedfordshire, and a 30-year-old from Kent, for the offences of Conspiracy to produce a controlled drug of Class C, Conspiracy to supply a controlled drug of Class C and Money laundering,” police told BBC Three. “All three have been released under investigation.”

Production of a Class C drug was a much more significant offence. If this was UKB, the kingpin of the counterfeit Xanax operation, then they had successfully brought down the key players. It was only a matter of time before charges were brought.

More than eight months after the first arrests, however, SEROCU says that no one has been charged.

Dark net vendors and forum users who say they know HBB claim he is on the run – and may have even fled the country. The police have not commented on what remains a live investigation.

The police operation appeared to end the mass production of alprazolam pills in the UK. Other dealers have come and gone, but buying fake Xanax is no longer as easy – or as cheap – as it once was.

Brad no longer has seizures, but he still goes to hospital for scans and check-ups. His entire friendship group has changed their approach to drugs.

“Everyone cleaned up their act,” he says. “The passing of a close friend made everyone realise we shouldn’t be doing that.”

“I was a version of myself I’d never want to be again.”

But across the UK, the story is far from over. The legacy of fake Xanax is that benzodiazepines have become a firm favourite for a new generation of drug users, in a patchwork drug culture that shows no signs of losing popularity anytime soon.

In recent weeks a new counterfeit alprazolam pill has emerged – this time mimicking a different pharmaceutical company. The same concerns about quality, consistency, adulteration and associated risks apply.

But these anxieties aren’t enough to keep teenagers from trawling the dark net for a way to keep the high going. And as long as they do, the dealers will be there, looking for ways to cash in.

*some names have been changed to protect the individuals.