Drug dealers are setting up cafes to peddle super-strength cannabis on Britain’s high streets, an investigation by The Mail on Sunday can reveal.

The Amsterdam-style shops, which attract customers via social media, are popping up in cities across the country.

In a phenomenon reminiscent of Prohibition-era speakeasies in the US, our reporters found:

Young people packing the secret cafes every night to smoke joints;

One ‘entrepreneur’ has registered his cafe as a business at Companies House;

Some of the cafes are selling a powerful cannabis strain known as ‘Cali (California) weed’ for up to £40 per gram.

Last week, our reporters visited two cafes in London and found both doing a brisk trade. Rich Nerdz, in Shoreditch, East London, served one of our reporters some cannabis

The bartender at Rich Nerdz is seen measuring out the cannabis. A menu offered a variety of strains including hybrid cannabis types such as ‘Gelato 41’, ‘Gusher’ and ‘Guava’

Our reporter offers the bartender some cash, which she accepts before handing over the cannabis. The reporter is then shown downstairs where users smoked spliffs, played computer games and chatted

Last week, our reporters visited two cafes in London and found both doing a brisk trade.

Rich Nerdz stands on a bustling high street and has a branded shop front. However, its tinted windows and the CCTV cameras monitoring the entrance ensure that most passers-by are oblivious to the venue’s real purpose.

It advertises itself on a private Instagram account – meaning new members must send a request to join – as ‘The New & 1st Ever (Cali) Gamers Cafe In The World…’, but doesn’t give away its location.

Rich Nerdz’s sole director, Khabeer Khan, 30, has registered it at Companies House as a bar serving food. He calls himself an ‘entrepreneur’.

A scene from Amsterdam... in London's docklands Sprawled across a leather couch, a young woman draws heavily on a cannabis joint while her friends sit sipping soft drinks and playing pool. It could be a typical scene from a coffee shop in Amsterdam, where cannabis was legalised almost 40 years ago. Yet this cafe is a closely guarded secret, hidden away behind an imposing black door built into an old railway arch in London’s Docklands. Anyone walking by wouldn’t give the venue a second glance. Entry to The Den – as those in the know call it – is granted only after staff scrutinise the security cameras overlooking the entrance and press a button to trigger the release of the door. Staff monitor CCTV at The Den cafe Once inside, customers find themselves in a sprawling room of neatly laid-out tables, high-backed bar-style leather couches and picnic benches. A pair of fish tanks accentuates the relaxed tone, as does the space-and-planets motif covering the curved ceiling. When The Mail on Sunday visited the venue last week, about 50 people were sitting around chatting and smoking in the cafe, which is thought to have been open for some five months. City workers in smart suits are known to frequent The Den, which is just a short taxi ride from Canary Wharf. Of the three members of staff we saw, one rarely averted his eyes from a bank of security screens monitoring the entrance, while another wearing sunglasses spent most of his time on the phone. A third, with eyes half shut, dealt out the super-strength cannabis. We chose the potent ‘Guava’ strain for £30 per gram from a menu perched on top of the bar counter. Around us, groups laughed and chatted. Some, evidently overcome by the strength of what they were smoking, fell asleep – despite rap music blasting out from the club’s sound system. The walls are adorned with posters – Marilyn Monroe, The Sex Pistols’ God Save The Queen single cover – and a huge graffiti sign proclaiming ‘The Den’. It feels a world away from the quiet residential streets. A steady flow of customers were also seen making their way up to the counter to buy their drugs, soft drinks or cups of coffee. The cafe is located just a few hundred metres from Limehouse police station, which was recently closed to the public but still operates as a base for officers. A Met Police source said that officers in the area were tackling a full spectrum of crimes and are now actively investigating information about the cannabis cafe after being notified by The Mail on Sunday. Advertisement

Our reporters messaged the account, which boasts almost 12,000 followers, and were placed on a guest list with a booking time. After a series of messages, we were guided to the cafe on a busy road in Shoreditch, East London.

Our team was frisked before being shown into the plushly decorated interior, with a bar counter displaying cannabis pots, alongside soft drinks and snacks in fridges behind.

A menu offered a variety of strains including hybrid cannabis types such as ‘Gelato 41’, ‘Gusher’ and ‘Guava’.

We were served by one of four members of staff behind the bar, before being shown downstairs where users smoked spliffs, played computer games and chatted.

A second speakeasy-style cafe known as The Den was found operating in Limehouse, East London.

The venue, located under a railway arch, has the appearance of a large social club with about 50 people inside smoking cannabis at any one time.

Our reporters were able to buy a gram of ‘Guava’ cannabis for £30 from a menu of strains available at the counter.

The cafe also sold soft drinks, snacks and coffees from a large coffee machine.

Tests at a specialist laboratory discovered both samples contained only the psychoactive THC, without any of the moderating CBD.

In the UK, it is illegal to sell cannabis substances containing THC, with the drug classified as Class B alongside amphetamines and ketamine.

‘Cali’ cannabis is typically made from hybrid strains which can contain psychoactive THC levels of up to 70 per cent compared with 15 per cent in UK varieties. Producers have developed stronger strains without CBD to have a greater psychoactive effect – but experts have warned of the dangers.

Ian Hamilton, addiction lecturer at the University of York, said: ‘With no CBD, you could get a range of possible effects – you can feel more anxious and on edge.

‘That’s the least that could happen, and the worst is several symptoms similar to psychosis. Some people will be all right but for others who are inexperienced, it could have adverse effects. The difficulty is people won’t know in advance whether they’ll be all right.’

He added: ‘THC is like the accelerator and CBD is the brake on the car that reduces the high and the psychoactive effect.’

Other secret cannabis cafes have been located in cities such as Birmingham, Manchester, Leeds and Newcastle but it is understood the venues are more temporary. MPs and experts have previously criticised the police for effectively decriminalising cannabis by the back door, with the drug linked to a host of mental health problems.

The latest Home Office survey shows cannabis remains the most popular illegal drug in the UK, with an estimated 2.3 million people using it in 2017/18, followed by cocaine on 880,000.

The most recent Public Health England statistics show cannabis was the leading single cause for new cases at treatment centres with 25,169 in 2017/18, followed by non-crack cocaine opiates on 18,767.

Last night the Metropolitan Police promised to investigate our findings. Sergeant Rob Rai, of Tower Hamlets Police, said: ‘The operation of premises for the sale and consumption of cannabis, often referred to as “cannabis cafes”, is an issue we deal with proactively.’

A second speakeasy-style cafe known as The Den (pictured) was found operating in Limehouse, East London. The venue, located under a railway arch, has the appearance of a large social club with about 50 people inside smoking cannabis at any one time

Our team was frisked before being shown into the plushly decorated interior, with a bar counter displaying cannabis pots, alongside soft drinks and snacks in fridges behind.

As well as cannabis, Rich Nerdz also sold soft drinks, snacks and coffees from a large coffee machine (a menu at the cafe is pictured)

A menu at Rich Nerdz offered a variety of strains including hybrid cannabis types such as ‘Gelato 41’, ‘Gusher’ and ‘Guava’. Our reporter was able to buy a gram of 'Gelato 41' (pictured)

Being let in the illicit den was like starring in a cheesy spy film

The instructions were elaborate but terse. Like actors in a hammy spy film, we were first requested to go to a bagel shop and await orders.

Then, right on cue, my mobile buzzed as a WhatsApp message was delivered. ‘Location is: 142 Bethnal Green Road. At arrival you will be by a bus stop.’

It was a two-minute walk across the heart of East London and we moved briskly. ‘Please stand by the bus stop as if your [sic] awaiting an arrival of a bus. Let us know you are there. You will be escorted in shortly.’

Once in position, we slipped into character, pretending to wait for the No 8. Suddenly, we heard the mechanical clank of shutters rising and we turned to see two doormen beckoning us inside what appeared to be an empty shop sandwiched between a vaping store and an estate agents.

The Mail on Sunday gained access to the illicit den, called Rich Nerdz, after responding to an advert on its Instagram page, which has 12,000 followers

After shaking hands and being frisked, we were led to a swish bar, the modern equivalent of a Prohibition-era speakeasy – except that this one served super-strength cannabis, in pots ranged across a counter, rather than hard liquor.

A blonde bartender invited us to look over the menu.

We chose ‘Gelato 41’, one of the most potent strains on the market, and an expensive £40 per gram.

As the bartender measured out our order, a screen behind her displayed the grainy feed from CCTV cameras monitoring the street outside.

Placing our cannabis and a couple of fizzy drinks on a tray, she then led us to a well-appointed basement area.

TV screens were fixed on to the walls and customers, sitting in booths, played computer games on PlayStations. Most, though, simply lounged around chatting and getting high.

One staff member told us that the cafe, which closes at midnight, would be selling its own food in a few weeks.

For now, they offer snacks and order in takeaways, so customers – who are required to spend a minimum of £40 between two – have no reason to leave.

As the bartender measured out our order, a screen behind her displayed the grainy feed from CCTV cameras monitoring the street outside

As groups of young men and women filtered inside, the room filled with the unmistakable aroma of marijuana. We spotted a rising US music star called Swoosh God, who has more than 80,000 followers on Instagram.

The rapper even filmed himself smoking joints in the cafe, later uploading the video to his Instagram page.

The Mail on Sunday gained access to the illicit den, called Rich Nerdz, after responding to an advert on its Instagram page, which has 12,000 followers.

It describes itself as ‘The New & 1st Ever (Cali) Gamers Cafe In The World… Coming To You From Shoreditch, East London’, before adding: ‘DM [direct message] To Be Put On The Guestlist.’ ‘Cali’ is a reference to the super-strength California skunk-like weed it sells.

At Companies House, Rich Nerdz, which opened its doors at the start of the year, is listed as a bar serving food. Its sole director is Khabeer Khan, 30, who lists his occupation as ‘entrepreneur’.

In order to approach the organisers for comment, the MoS called the same number used by the Rich Nerdz cafe to direct guests to the venue. The number failed to connect but we followed up with a WhatsApp message and received a response threatening legal action for filming in a ‘private location’.

The messages were quickly deleted by the cafe’s branded WhatsApp account.