A failure to grasp how technology and social media is being used to coerce, control, blackmail and track the movements of children as young as 11 by “county lines” drug gangs has seen an epidemic of child criminal exploitation spiral out of control in the UK.

“For the past seven or eight years we have been warning the government, the authorities, teachers, anyone who would listen, that technology is the central organising feature of the county lines business model,” said Sheldon Thomas, a consultant on gang behaviour through his organisation Gangsline.

“Social media and smartphones made kids easy pickings for drug gangs and once they use this technology to track and control children it is very hard, often impossible, to extract them from this world,” he said.

Last week the National Crime Agency (NCA) revealed that the scale of the county lines trade, in which criminal networks use children to funnel drugs from cities to towns and rural areas, was far greater than previously thought. New figures from the NCA show the trade has grown into a £500m industry.

“This is a crime that is fuelled by the criminal exploitation of vulnerable young people, who are often being groomed and radicalised online,” said Rhiannon Sawyer, a manager at the Children’s Society. “Children don’t need direct contact to be recruited and brainwashed on YouTube, Snapchat or Instagram.”

The victim is made to feel that they are constantly under surveillance and their every move is being tracked

Drug gangs have long used music videos on YouTube to present gang life as aspirational but in recent years individual gang members across the country have also amassed huge followings on Instagram and Snapchat, becoming social media influencers to young people in their area.

“When an older gang member – who is often like a local celebrity in their area – is taking the time to like or comment on your photos on Snapchat or Instagram then this is a huge deal to kids,” said Thomas. “It’s not hard to make them feel special and singled out. It’s all very public.”

Snapchat is used heavily as a recruitment channel, with gangs posting clips of children in trap houses with new trainers, piles of money and weapons.

“We’ve seen Snapchat posts with very young children posing with £30,000 in cash,” said Sawyer. “Gangs have always glamorised their lifestyles to suck in new recruits, but the growth of platforms like Instagram and Snapchat has moved this to another level.”

Once children are recruited, social media is often used to coerce and blackmail them, and track their movements.

Sawyer said she regularly works with young people who have been filmed by gangs being sexually abused, beaten and humiliated.

“Often, gangs make boys touch each other or undress, or young people are filmed having drugs inserted in their rectal passages or vaginas … and then they threaten to put these posts online if the young people don’t do what they say,” she said.

Sawyer added: “Sometimes they deliberately put the videos online and then after a month you’ll see the same child on Snapchat in a trap house [on] the other side of the country, trying to rebuild their dignity by showing that they are climbing up the gang hierarchy. We recently saw this scenario with a 12-year-old boy.”

Smartphones are also being used as tracking devices through apps like Find My Friends to monitor the movements of children transporting and selling drugs across the country. This practice, known as “remote mothering”, sometimes involves young people being forced to live-stream their movements 24 hours a day on WhatsApp or FaceTime.

“We’ve seen this regularly with domestic violence and honour-based crimes where the victim is made to feel that they are constantly under surveillance and their every move is being tracked, and this is happening with county lines,” said Sawyer.

“This is extremely traumatic and isolating. Young people who want to exit [gangs] don’t feel they’re able to seek help because the gangs will know where they are. We had one teenage boy who came in to one of our services and wouldn’t sit down. He just walked around and around the room because he was so paranoid that if he stopped moving they would find out where he was.”

Gang members send children pictures of their mother’s front door when they are on an operation and threaten to firebomb the house if they stop working for them. Young people are told their phone must be switched on and charged at all times and they must answer it within two rings, or they are threatened with violent repercussions.

“They have complete control of children through their phones,” said Sawyer. “There is nowhere for them to hide.”

Failing to tackle the use of mobile phones and social media by drug gangs to coerce and control young people has contributed to the huge growth in county lines drug operations, said Thomas.

“In many ways it’s too late to get a grip on this,” he said. “We were warning the government and the police about this almost a decade ago but nobody took any action, and now it’s got to the point where the state is trying to play catch-up with a situation that has moved far beyond their control.”

One solution, he said, would be to invest more in mediation and peer-to-peer mentoring schemes where young people can meet others who have gone through similar experiences.

The Children’s Society says official guidance and protocols around how social media is used to exploit and coerce children into criminal activities must be integrated into statutory services designed to tackle county lines operations.

“This is often an invisible form of coercion and exploitation that is happening without any adults being able or willing to intervene,” said Sawyer. “For these young people there is no difference between the online and offline worlds and we have to tackle this because we are facing a national crisis and this problem is only going to get worse.”