As the volume of cocaine trafficked into the Netherlands through the port city of Rotterdam increases, so too does the number of young men employed by criminal gangs to retrieve the drugs from among freight arriving from Latin America. The BBC has had a rare glimpse into the dangerous work of these so-called "cocaine collectors" who provide a vital link in the European narcotics supply chain.
On a flickering CCTV screen, a dozen shadowy figures run with military precision in a line towards a shipping container in the port of Rotterdam.
Its freight of tropical fruit from Colombia may already have been unloaded, but this metal box - 12m long and identical to so many thousands of others here - still has cargo on board. Eighty kg of cocaine are hidden inside the refrigeration unit - drugs with a local street value of around 4m euro (£3.4m).
The collectors' job is to get the drugs out of the container and away from the docks, from where they will be transported to Amsterdam, Berlin and London.
"The port's a goldmine! It's beautiful," a man, whose face is obscured by a mask and a hood, tells journalist Danny Ghosen on his show, Danny's Wereld, on the Dutch TV network, VPRO.
"I can make money nice and close to home... and there's always work."
These are young men employed by powerful, criminal networks.
"Every job's different," the man explains. "One boss will say, 'You'll earn X amount to share between you'. Another will say, 'You'll get some of the drugs to sell for yourselves.'"
We recently found three ‘hotel’ containers. The collectors might stay in one for days. We find mattresses, empty bottles of water, food wrappers...
Collectors make around 2,000 euro (£1,680) for every kilo of cocaine they carry out. And this is a business that has exploded.
"We first noticed them about two years ago," says Andre Kramer, who owns a container processing company in the port.
"There was one or maybe two of them, and it happened once or twice a year. But in the past six months the groups of collectors have got bigger - 10 or 12 people gathered together, and it happens three or four times a week."
As the volume of cocaine imported into the Netherlands rises exponentially, the methods used by the collectors are becoming more sophisticated too.
Sometimes they don't physically take the cocaine out of the port. Instead their job is to transfer the drug to another container earmarked by the gang with the help of an insider, which will then be transported out of the port by truck. And sometimes the gangs will wait inside the port area for a drugs shipment.
"We recently found three 'hotel' containers," says Kramer. "The collectors might stay in one for days - they eat, drink, and do their necessities in there. We find mattresses, empty bottles of water, food wrappers…"
But biding your time in a "hotel" container waiting for the coast to be clear can be extremely dangerous.
In early September, nine young men found themselves trapped after the door to the shipping container they were hiding inside - partly packed with a freight of tree trunks - became jammed.
We had information that 9 people were going to die in a container - but it’s in a terminal amongst 100,000 other containers, and the collectors didn’t know exactly where they were
"If you're enclosed with biological matter like fruit or wood, these things still use oxygen, which means less for the people inside - so the air gets thinner," Jan Janse, chief of Rotterdam's Port Police explains.
"Normally they take care that they can open the container from the inside, but something went wrong, and they couldn't get out."
With panic rising along with the temperature, the collectors dialled 112 for the Dutch emergency services.
"So we had this information that nine people were going to die in a container, but it's in a terminal amongst 100,000 other containers, and the collectors didn't know exactly where they were," Janse says.
"We had to search the whole premises - there were helicopters, a lot of police, customs officers, the fire brigade, ambulance services. They were lucky we found them on time."
It took four hours. Some of the men were hospitalised with respiratory difficulties. But for security reasons Janse, who has been the chief of police here for seven years, will not reveal how they found the collectors.
"Let's just say we did some smart things," he says, enigmatically.
In 2014, the Rotterdam authorities intercepted more than 5,000kg of cocaine in the port. By 2020 it was a whopping 41,000kg.
"This year we reckon it's going to be 60,000 kilos," Janse says. "We break the record every year. I'm not proud - it's good we seized the cocaine, but every year there's a larger amount coming in."
And the narcotics discovered in the port represent only a tiny fraction of illicit imports.
In September, 110 collectors were apprehended in the port area in just over a week. But unless they are caught red-handed, they only risk a fine of less than 100 euro (£84) for trespass. Some collectors even carry cash so that they can pay penalties on the spot in the event that they are stopped.
"We say, 'We're just having a nice walk… We're fascinated by containers'," says the masked young man who makes his living moving narcotics out of the port.
"Do I have anything with me? Do I have drugs? Or tools? No, I've got nothing on me."
At 42km long, the port of Rotterdam is the largest in Europe. More than 23,000 freight containers are processed here every day. And central to the work of the cocaine collectors and the criminal organisations they work for is one critical enabler: corruption.
"If you come here tomorrow morning, I guarantee you can get hold of a security pass. You just say to a worker, 'Lend me your pass until tomorrow, and you can earn 500 euros'," says the collector.
"It's hard to do our job without someone on the inside, like a customs officer. He could have a container that should be inspected, but he takes it off the inspection list for you."
And if an insider refuses to co-operate the collectors use intimidation.
"The moment a customs officer says, 'No,' you threaten his kids," the masked man says ominously. "Then he's going to say, 'Yes' very quickly."
Andre Kramer says his employees are under pressure because they are in the sights of those working for organised crime.
"People are being approached at home to place containers near a fence, for instance," he says. "And I've actually had staff giving in their resignation - they don't want to work here anymore - they're scared."
Rotterdam's chief prosecutor is familiar with these stories.
"A lot of criminality in the city has some connection with the drugs problem in the harbour," says Hugo Hillenaar. "We have a shooting incident almost every day. Ten years ago, it wasn't on the streets. Now the violence is increasing."
And the bloody repercussions of the cocaine trade extend nationwide - including the audacious, daylight assassination in Amsterdam in July of the Netherlands' most famous crime journalist, Peter R de Vries.
It’s easier to raise happy children than to repair broken men
"The criminal organisations are very well organised - they have their CEOs, their human resources, they have staff and recruiters," says Nadia Barquioua, founder of JOZ - an organisation supporting young people.
JOZ runs youth projects on Rotterdam's south bank - one of the most deprived urban areas in the Netherlands and where many of the city's cocaine collectors come from. More than a quarter of the population is under 23, and more than half are from a migrant background.
In the 1960s and 70s, people from outside the Netherlands settled here, attracted by employment opportunities in the port. But when industrial activity moved west to accommodate the mega-ships and the work dried up, those who could afford to move away did, leaving a large number of low-income households.
JOZ works through schools, clubs and in community centres in an attempt to divert young people away from crime.
"We must show them that making money in a normal way is much safer than doing it in a criminal way, and that they have opportunities in the city," Nadia Barquioua says. "It's easier to raise happy children than to repair broken men."
There is a growing number of young men working as cocaine collectors in the Port of Rotterdam.
"We have boys of 14 or 15 doing this job, and that's worrying," says Hillenaar, "they're becoming younger and younger."
"Every day in the city of Rotterdam, 40,000 lines of cocaine are sniffed. Each line has a history of violence, extortion, and death
There's talk of a "white Christmas" in Rotterdam - but no-one is referring to snow. Ahead of the festive season, Hillenaar has a message for cocaine users.
"Every day in the city of Rotterdam, 40,000 lines of cocaine are sniffed," he says. "Each line that you sniff has a history of violence, extortion, and death."
Hillenaar hopes a change in the law that comes into force in 2022 will be a strong deterrent to the collectors. It dispenses with fines and imposes a prison sentence of up to a year on any unauthorised person found in the port area. But given the vast amounts of hard cash that can be earned as a collector, not everyone is convinced it will work.
"I honestly do not think you're going to stop drugs coming into the port of Rotterdam," says businessman Andre Kramer.
He's also worried that upping the penalties and threatening a prison sentence may provoke violence in the port area.
"Today, the collectors will leave quietly. But it's going to be grim when they will use anything to try and get away - weapons, knives…You don't want some sort of Wild West show going on in your terminal."
For some young men, the threat of a jail term may well make them think twice before donning dark clothes, and breaking into one of Rotterdam's container depots. But given the big bucks on offer, others will be less easily deterred. They know they are a vital link in Europe's cocaine chain, and that this is a business that is not going to end any time soon.