It's true there has been a rise in gang-related violence, particularly knife crime, outside the major cities, and that the proliferation of young drug dealers " going country " to sell crack and heroin in rural and coastal towns is contributing – if not driving – this. But there is a danger here of swallowing a simplified narrative: of faceless inner-city thugs bringing death, addiction and destruction to otherwise sedate home counties and peaceful rural backwaters.

The story, of course, is more complicated than that. But if Britain's crime map is being redrawn, and violence and gang-related crime is expanding outwards from our urban hubs, how exactly is this happening and who is involved?

In the last decade there has been some grumbling from locals about the number of "foreigners" moving into the area. In 2010, Neil Rockliffe – a Tory councillor for Chafford Hundred, a new-build settlement popular with Nigerian families from south and east London – was forced to step down after referring to his constituency as "Chaffrica".

It's fitting that the Daily Mail is printed here. Like much of Essex, Thurrock – a traditionally white working class area – is Brexit Country, polling one of the highest Leave votes of any constituency in the 2016 EU referendum. It's now Tory, but in the 2015 general election UKIP came within a few hundred votes of having an MP in Thurrock.

In search of some answers, I headed up the Thames Estuary to the borough of Thurrock in Essex, an area, like many parts of Britain, experiencing a rising presence of London gangs. It's only 30 minutes out of London on the train, but Thurrock is a limbo-land. Best known for the huge Lakeside shopping centre and Tilbury Docks, it's neither urban, suburban nor the countryside. Fields of horses and verdant river banks merge with nondescript town centres, bleak housing estates and heavy industry.

But now local concern has shifted to the looming presence of London drug dealing gangs. As Labour councillor for Tilbury, Steve Liddiard, warned in April : "Drug dealers are in every road. The gang culture is developing. Young men [of] 13 upwards are being groomed."

This rise in violence is, unfortunately, not restricted to Thurrock alone. "Over the past five years, knife crime has been growing in areas surrounding large urban centres," Callyane Desroches, a Senior Policy Analyst at criminal justice consultancy Crest Advisory, told me. "This is particularly true of areas surrounding London, such as Essex, where knife crime is up by 116 percent."

There has also been an uptick in gang violence here linked to London drug dealers. In March, two dealers from London were jailed for murdering a local man in Thurrock's South Ockendon. Last December, a 20-year-old from London was charged with the murder of a local heroin user. Acid attacks have also increased. A local court house banned all drinks bottles in fear of gang members using acid to attack rivals or staff.

He's got a point, because dealers affiliated to the London gangs are all over Thurrock, as they are across Essex in Southend, Clacton, Colchester, Harlow and Chelmsford. In response to this new problem, in 2014 Essex police set up Operation Raptor, tasked with hunting down drug dealing gangs from London. In 2017, Raptor made 668 arrests, seized drugs with a street value of £684,530 and locked up those involved in drug and gang-related crime for a total of 336 years.

A decade ago, many of these families were being relocated to outer London boroughs; now, they are being sent out of London altogether. Between 2012 and 2015, Newham, Barking & Dagenham, Greenwich, Redbridge and Waltham Forest councils sent 448 homeless tenants – the majority of them in families – to Thurrock, more than any other area outside London.

"Some families from London chose to move here to get their kids away from the gangs," says Ceryl. "I think the families believed that Thurrock would offer them better outcomes and opportunities. Others were placed in Thurrock involuntarily because they were homeless or had been evicted for anti-social behaviour or because of gang tension." She adds that some families told her they had been re-housed in Thurrock because their sons had been involved in the London riots in 2011. Others said they had been encouraged to relocate out of the capital as councils prepared for the London Olympics in 2012.

Ceryl Marsh, now an independent gang worker, has worked with young criminals and their families at Thurrock's youth offending unit for 13 years. She has seen first-hand the expansion of gangs out of London into the area, and was herself threatened with violence by one of the London boys. She says the drivers behind this are far more complex than simply "county lines" – London gangs have also been in part enabled by the capital's housing crisis and the clumsy relocation of some of London's most vulnerable families and at-risk young offenders, often with very little afterthought.

"Some of the relocations for high-risk families or offenders took place without us being notified," says Ceryl. "So the first we would hear was when someone had been arrested and we’d find out they had been living in Thurrock for a few weeks. This proved difficult, especially when they’d been moved due to threats to life from one gang, and you find out they’ve been moved into a small area where the gang they are at significant risk from also have people living."

For teenagers with gang affiliations, being re-housed – a gang exit strategy advocated by the Home Office – did not work in Thurrock, according to Ceryl. "Thurrock was so close to the boroughs they were moving them out of, it didn't work, because they could jump on a train and be 'home' in 30 minutes."

The move worked for some families, but not for others. Coming to Thurrock was not easy for them. "They lived here, but they weren't integrating locally," says Ceryl. "Their kids were still going to school or college in London, so they weren't wanting to be 'local'."

"Now, Thurrock is a diverse place – it's a good thing," says Ceryl. "You've got a good ethnic mix, some African hairdressers and cafes, Polish stores. But at the same time, these tough new drug dealers from London came, with a negative attitude to police because of stop-and-search and the riots. For us, they were tough to engage with. We earned our money."

Ceryl shows me a well-produced YouTube video complete with drone footage showing one of the crews – a London gang known to the Home Office, now operating out of Thurrock – hanging around a Porsche and singing about stabbing people and dealing drugs, in Grays, the largest town in Thurrock. The footage shows them crowding around a confused-looking police officer sitting in a car, who probably has no idea he has been viewed 64,000 times on YouTube.

Some young offenders who were moved to Thurrock used it as a bolt-hole, stayed out of trouble and went to college. But others took advantage of the change of scenery. They began selling in Essex for the London gangs, sometimes working with rival gang members because they were free to do what they wanted outside of the city. "I think the relocations also eventually saw the blurring of lines in terms of people from opposing gangs hooking up to have 'numbers' in this area, rather than being at risk or outsiders locally," says Ceryl.

Driving around Tilbury, Ceryl points out the flats where the Newham boys from Stratford do business, 200 metres from where the Custom House boys are located. "They've all been moved by London authorities and now they are on each other's doorstep," she says.

For the London gangs, Thurrock – with its high number of struggling working class families – is not just a place to sell drugs or a spring-board to markets further afield, but an ideal recruiting ground. Ceryl says one London gang member, who was attacked by local Thurrock dealers with a hammer two years ago before asserting his authority in the area with knives and acid, has signed up for college in Basildon, Grays and Southend purely to recruit drug sellers.

A five-minute daytime stroll through Grays town centre, best known for producing Russell Brand and the woman who was photographed pissing on the town's cenotaph , reveals a surprisingly open drug market. Young dealers are laughing, playing music and serving up crack and heroin on the high street opposite the main council building as office workers head for lunch. Round the corner, outside St Paul's and St Peter’s Anglican church, a team of dealers sell in the graveyard and the alleyway, watched over by lookouts at Grays train station.

Ceryl says the rising tide of London crews in Thurrock "shook up" the local crime scene. "It's so insular here, a lot of street gangs thought they were the big guys until the London crews came, but now they are silent," she says, adding that she warned police eight years ago that incoming London dealers were starting to recruit local kids, cuckoo local drug users' homes and create gang tensions in Thurrock, but says she was ignored. "Now it's easy for anyone to go trapping for a week if they want to go and buy their sister a birthday present," she says. "A lot of the kids are doing it now, and a lot of them are carrying knives – it's become a more acceptable thing to do for kids from all walks of life."

When they accused him of stealing money he had to work off his debt by trapping in Norfolk and Suffolk. His mum reported him missing the first few times, but then gave up and he was booted out of school. In Norfolk, he was caught with a large amount of class As, but dodged jail because of his age. After four years of trapping for the London boys and having knives pulled on him, he says he’s in control, a level up from the new recruits. In reality, Ceryl says he's still at the bottom of the rung.

Ceryl tells me about one teenager from Grays who was 13 when he was groomed into selling crack and heroin by members of a crew from east London who had settled in Thurrock. Gang members bought him food, took him out for a spin in their cars and gave him money for his mum’s birthday. Soon, he was nipping over on the ferry from Tilbury to Gravesend in Kent (child fare £2) to deliver small packages of crack and heroin for £500 a week.

Arriving in Essex, it was easy for him to reprise his source of employment for the east London gang – as a specialist in robbing cannabis grows – because they were here already. Since coming to Thurrock he has crossed the paths of several other London gangs, and burgled cannabis farms for them too. Danny estimates he's robbed 150 illegal cannabis factories of their crops, the proceeds of which he splits with the gangs who provide the tip-offs. Sometimes he has gone seeking out cannabis farms himself, using a handheld heat-seeking device designed for plumbers.

Behind an abandoned shopfront in Tilbury, we meet 20-year-old "Danny" (not his real name), a highly proficient cat burglar who was moved to Thurrock from east London in 2014, as an alternative to a jail sentence. He’s had a front row seat as various London crews have come to dominate Thurrock.

Danny has worked with rival London gangs on the same job: "I had two boys from rival gangs in the back of the van on the way to a cannabis burglary last year, even though they had been slagging each other off on YouTube the day before. Any other circumstances they would be at each other’s throats. Life ain’t nothing to them, but because it involved money, that changes everything."

"The London gangs have been in Tilbury for about five years, they’ve slowly been creeping in," he says. "First, I made friends with the locals, the Tilbury boys, who are hillbillies. I call them Sylvanians, because everyone is family, everyone knows everyone. They don’t like the black boys from London. It's a badly racist area. Now, more of my friends are London lads. One of them is reckless; him and his boys will squirt [acid] or stab someone over nothing. He’s now one of the main dealers here."

Although he was used to trapping around the country, life in Thurrock did not suit him, even though he had been the subject of death threats in his home town. "I wanted to leave straight away," he says. "I told my dad, 'I'm not fucking living here. I'll help you unpack your stuff, but the shops are half an hour away.'"

For some Londoners, being shifted out to Thurrock can exacerbate their sense of disconnection. "Lewis" (not his real name), now 18, was moved from a north London borough with his father and brother to Thurrock for his own safety. His mother stayed in London. He had been heavily involved in "going country" from an early age, selling crack and heroin in numerous locations including Cambridge, Nottingham, Northampton, Winchester, Norwich, Andover, Basingstoke and Boreham Wood. He had also been involved as a victim and perpetrator of knife crime, and was a 24/7 knife carrier.

Lewis spent most of his time dealing drugs back in London. But because he had officially moved to Thurrock, he was left to drift, a 16-year-old in serious danger of being murdered – yet effectively off the radar. His only contact with the authorities was with Ceryl at the youth offending unit in Thurrock, as a condition of his bail. "All my teachers at school told me was that I would end up dead or in jail," he says. "No school I’ve ever been to has helped me. They’ve just brushed me aside. I got told I was worthless. It broke my spirit. But Ceryl was the first person who encouraged me."

Even though Ceryl was making headway with Lewis, when his mother died he became angry and nihilistic; he "wanted to kill or be killed" and ignored increasing warnings from a rival gang that he would be stabbed if he stepped into their territory. Last year he was chased down by a mob and slashed and run through with a machete in a north London high street. He shows me one wound where the machete entered his back and came out of his stomach. Sitting on a bench in a London suburb that he was moved to by Operation Trident for his own safety, Lewis remembers sitting down after being attacked, eyes closing as a pool of his own blood spread out beneath him on the pavement.

He was taken in for emergency surgery and survived, but the next day his best friend, who had promised to visit him, was stabbed and ended up losing his fight for life on the same hospital ward. When I ask Lewis about the connection between rising violence and county lines, he says: "We started off just kids trying to earn money. Now, no one cares about the drugs, they are just killing each other."

Back in Thurrock, Ceryl says there is a new breed of teenagers growing up with an attitude to violence that has been normalised by the London gangs' presence here.

"Imran" (not his real name), a 14-year-old schoolboy from Grays, was caught two weeks ago with a ten-inch hunting blade. "A 'friend of a friend' told him he needed to carry a knife to protect himself," says Ceryl. "He started associating with local gang nominals who were older than him. That added to his reputation locally. He wanted people to be afraid of him, wanted others to know who he was and not to mess with him. He’s very clever, but he wants the 'thug life' too much. His leadership skills are likely to be used to pull others in. He has the ability to come away from it all and the support around him to do so, but is choosing not to. I fear he's lost to them already."

Thurrock is not the only area experiencing these kinds of problems; this is a phenomenon being repeated across the country. Once buffered against the extremes of inner city crime by being "out there", satellite towns and rural capitals are now having to adjust their tactics, at a time when police and councils are struggling to make ends meet.

But as more and more people get priced out or dumped outside the major cities, and city gangs continue to snowball across Britain as they use commuter towns to consolidate and recruit, this urbanisation looks set to run and run. Unless the root causes of gang affiliation – bad education, racism, claustrophobic living and lack of opportunity – can be addressed, then it is inevitable that the fruits of inequality will come knocking, wherever you live.