Not long after his first foray, the Midlands Special Operations Unit was set up – they would provide Neil as an asset to police forces across the country, who wished to set up similar operations in their own jurisdictions.

The forces he worked for weren't allowed to know his real name or origin, and officers would be disciplined if they even asked him for personal information – his pseudonym was used both behind closed doors, and on the streets.

So it was he'd pitch up in major cities, posing as a "travelling scally" (itinerant thief), decked out in Nike Air Max trainers and a tracksuit, looking for people to score from.

His method of making contact and connections with top druglords was to appear extremely vulnerable – moving among the flotsam of a city, consorting with rough sleepers and the like.

"They use more drugs than anyone else, so have the best connections, and were easy for me to manipulate. They'd introduce me to all the local runners and gangsters, and I would steadily increase amounts I was buying, networking along the way. My ultimate targets were regional mid-level wholesalers," Neil told Sputnik.

However, he soon found his operations were lasting ever-increasing stretches of time, and was compelled to go increasingly deeper undercover as a result.

Given the milieu in which he operated, it's no surprise Neil had extremely close brushes with fate on numerous occasions.

For instance, in a deployment in Northampton, his target was the notorious Burger Bar Boys, who for two decades wreaked havoc in the area, claiming dozens of lives in the process – the gang had a built a fearsome reputation, using rape as punishment for unpaid drug debts.

While the operation was successful – he helped convict 96, six of whom were sentenced to a decade in prison each – it almost came unstuck in epic fashion. After four months, he began using a hidden camera to document their activities. This continued for three weeks - and one day, his targets seemed to become extremely suspicious of him.

The next morning, he opted at the last minute to leave the recording device at home. It turned out to be a very wise move.

"Hours later, I was snatched off the street by five of them – they accused me of being an undercover, drove me to a racecourse, and stripped me naked at gunpoint. I thought that was it for me – one of my kidnappers was implicated in seven murders. They let me go though, because they didn't find anything incriminating," Neil explains.

On one occasion however, his hidden camera was found. Near the end of a deployment in Leicester, Neil sought to secure footage of a gangster he'd been buying heroin from. He contacted the individual, offering a cache of counterfeit clothing for sale, and met him in a car park.

The dealer brought along two friends, one of whom was extremely suspicious of Neil - he shoved him against a wall and started aggressively rummaging his clothes, until he found a "telltale hole" in one of Neil's jacket buttons.

"I swore at him, saying he didn't know what he was talking about. He wasn't expecting that. I put the clothes away slowly, still subjecting him to a torrent of abuse, before walking away. He was trying to convince the dealer I was a cop – but I'd known the guy six months, and he wouldn't believe it. He was reassuring his mate I was fine, giving me a small avenue to escape," Neil told Sputnik.

Nonetheless, the dealer's friend evidently eventually persuaded him of Neil's real identity, because he heard their car start up and race towards him, right as he neared the exit. He started running, but before long they'd caught up, mounting the pavement. Neil barely managed to leap a protective railing and get to safety – the car had been within two meters of him.

In another stroke of unbelievable luck, in an operation in Nottingham, he'd spent four and half months trying to get an introduction to a lieutenant in the Bestwood Cartel, run by the infamous and appropriately named Gunn brothers.

As Neil records, such was the gang's reign of terror, shootings were a daily occurrence, and newspapers called the city 'Shottingham'.

The day after he finally got his introduction, he was to brief local police on his activities, but two of the regular team were off sick. Replacements were sent in their place, and had an introductory chat with Neil – one was "fine," the other made the hairs on the back of his neck stand up.

"When you're an undercover, your senses are fine-tuned to the point of paranoia. I felt there was something wrong with him, so said I couldn't have him know what I was doing. he didn't question me or receive my briefing. Later, it was discovered he'd been passing information to the Gunn brothers for a fee for over seven years. He'd provided intelligence that led to several murders," he sighs.

His uncanny sixth sense undoubtedly saved his life – at the time, the Gunn brothers had put word out on the streets that if they caught an undercover cop, the officer in question would be kidnapped and tortured to death.

After many years of successful operations, Neil came to an extremely uncomfortable realization. Far from liberating communities from villains' pestilential clutches, he'd merely "trampled on the vulnerable," and made the streets an even more dangerous place in the process. Moreover, he came to believe the entire drug war was "completely futile," having "no impact" on the trade at all.

"I spent a lot of time making the lives of vulnerable people even less bearable. I put drug dealers in prison for a combined total of 1,000 years, but only ever interrupted the flow of heroin and crack in a city for about two hours. The same people at the top kept getting rich, however much authorities cracked down on it," Neil told Sputnik.

During his deployment in Nottingham, one of the people he chose to manipulate was an individual named Cami - a minor footsoldier in the Bestwood cartel on bail for selling heroin, and a "perfect" target for Neil.

He had all the connections Neil sought, so he befriended him, shoplifting goods and bringing them to Cami to sell. One day, he gave his target a present – a new baseball cap. Cami was "ever so pleased."

"At the end of the operation he was arrested. In custody, he was placed on round-the-clock suicide watch – he told officers I'd been his only real friend, and the only person he could talk to. My actions also put him at increased risk – he'd be known as the numpty who introduced the undercover cop to the cartel, and get more jail time, when quite clearly he just needed help," Neil laments.

Before the operation began, Neil knew these were likely consequences of targeting Cami – but he felt the end justified the means, that causing harm to him and others was a price worth paying to catch major gangsters.

More significantly though, Neil realized the reason gang violence got worse every year, with ever-more violent tactics employed, was down to people like him.

"The penny dropped. It's a Darwinian situation. If you're a drug dealer and want to protect your business from police attention, you increase fear. If you can intimidate a community into not grassing you up, you're successful. The most violent rise to the top. This is an inevitable, direct result of undercover infiltration and the use of informants," Neil told Sputnik.

Neil was recalled from the undercover frontline in 2007, becoming a detective then detective sergeant. He was keen to use his insight and experience to transform drug policing and policy, but soon realized it was a fruitless endeavor – achieving change from within was impossible.

He left the police in 2012, and it was not long before he was thrust into a pronounced psychological crisis – diagnosed with post-traumatic stress disorder of a very specific kind, driven by guilt over the harm he'd done. This variety of PTSD is known as "Moral Damage" – it's typically suffered by war veterans.

"My various near-death experiences obviously contributed negatively to my mental state – but when I lay awake at night, those weren't the memories that dominated my mind. No, it was the faces of people I'd hurt, like Cami. There are so many things the public doesn't know about the drug war – I became convinced that with the inside knowledge and experience I had, it was my duty to tell them," Neil told Sputnik.

As a result, Neil joined international organization Law Enforcement Against Prohibition (LEAP), becoming its UK chair in 2015 – a book documenting his experiences and reform ideas, Good Cop, Bad War, was published March 2017.

Beyond saving taxpayer money wholly squandered on fighting a "senseless" battle, and stripping criminal elements of their most lucrative commercial venture, Neil believes drug regulation – particularly in respect of cannabis – is a child protection issue.

Less than one percent of UK teenagers can buy alcohol from licensed premises, but over half have easy access to cannabis – in inner city areas, that figure is even higher. Moreover, in addition to ending teenage drug use, he notes organized crime recruits via the cannabis market, turning low-level purchasers into lieutenants with the allure of easy money.

"Again, the exploitation of young people by criminals is a direct response to police tactics. If people like me weren't so successful, children wouldn't be used by gangs now. Getting them to hold and/or sell drugs is a great defense – it's borderline impossible to embed an undercover in a teenage racket. Also, they're highly disposable, easily manipulated, and readily bought. These are urgent child protection issues, and current policy has no answers for dealing with them," neil concludes.

Given the illicit drugs market is worth £10.7 billion annually in the UK alone, and the prohibition of drugs costs taxpayers £16 billion every year too, lawmakers may be well-advised to at least give Neil's arguments a fair hearing.