The cars - hundreds of them - would start gathering as the sun went down.

Full of young party-goers, the process was simple. The date of the event would be flagged up on printed flyers and distributed to record shops and revellers outside nightclubs.

They would be circling the M25, tuned into a pirate radio station, and details of where they needed to go would be revealed shortly before the event got under way.

On one warm summer's night in August 1989, the place to meet was near Brands Hatch, an easy stop-off, close to the motorway junction.

There the fun-seekers discovered where they were set to dance the night away.

And on this particular evening it was a field in nearby Happy Valley, Meopham.

What they didn't realise as they set off - following the car in front in a giant snaking convoy - was that they were about to attend a defining event for the county during what was dubbed the Second Summer of Love. This was the era of the illegal rave and thousands couldn't get enough.

Emerging from clubs and house parties, police crackdowns had driven the events into rural areas. And Kent was ideally placed.

Huge sound systems blasting out acid house music, professional lighting rigs - all fuelled by an enormous boom in the use of 'love drug' ecstasy - raves terrified villagers who feared one on their doorsteps, and left the police caught, initially at least, on the back foot.

As the party organisers were setting up, Chief Superintendent Ken Tappenden, divisional commander for north west Kent, could have little idea of how this sub-culture was about to change his life for years to come.

Now retired, the former officer, who lives in Medway, remembers: "The first raves concerned us very much.

"The biggest one we had straight away was the one at Meopham - a whole field was taken over. We were quite unaware of it. Some 5,000 people turned up.

"By the time we got there, fairground attractions, ordered from the Midlands, were being set up. There was nothing we could do. They'd hired steamrollers and flattened the field first - again all unbeknown to us.

"That rave went on for nearly 48-hours.

"Two days later we were still finding young people, in ditches around the area, still under the influence of drugs."

It wasn't the first time Tappenden had encountered this new breed of unlicensed events.

In the September of 1988, around 250 people had taken over a derelict house in Sevenoaks and started to party. Hard.

As police arrived to break it up, skirmishes erupted and both police and partygoers were left injured.

Calling on back-up from the Met Police, it took 60 officers some two hours to restore order.

By the end of the evening, more than a dozen arrests were made and the 'Smiley' face - which would become synonymous with the acid craze - was left daubed all over the building.

Following that, Tappenden and his team had formed a unit to keep an eye out for future disturbances. By the summer of 1989 it was spearheading the national push to crackdown on raves.

The Pay Party Unit, dubbed the Acid House Squad by revellers, ("the government didn't want us to call it acid or rave" he recalls) was up and running and it meant business.

"We started the unit in Dartford, as they had taken over a disused hospital there and raved for 24-hours and then smashed it up.

"The next thing was they were going to throw parties all around the M25. Kent was taking a real bashing.

"I became the national co-ordinator," he says, "I was up and down the country advising chief constables on how to tackle these parties."

He would not have a weekend off for the next two years as the number of parties spiralled out of control.

At its peak, he remembers having 126 raves each weekend taking place anywhere from the Midlands down to Kent. In the county alone there were between 20-25 every Saturday.

The weekend following the Meopham event, another was organised for Wrotham.

This time, Tappenden thought he'd got the edge on the organisers.

"I got an injunction and so I personally went to serve it on the landowner.

"But when we got there, we found he'd been given £3,000 in his back pocket by the organisers and told to spend it on a holiday in France for the weekend, so we were stuck.

"There were up to 9,000 people at that one.

"But the Wrotham one was the first one we raided as they were coming out. We took out six black sackfuls of amphetamines and drug paraphernalia.”

Another event, planned for Chatham’s dockyard was nipped in the bud – but only after throwing up road blocks around the area.

The police found themselves in a permanent game of cat and mouse.

"The worse one on the M25 was at Junction 4 [for Cobham, in Surrey] when we put a road block up,” remembers Tappenden.

“The youngsters just parked their cars on the side of the road - it must have stretched for more than half-a-mile - got out of their cars and just threw their keys into the hedge - and then we were snookered.

"That stopped the motorway, and that made everyone anxious and angry. That's when it got serious.

"The local authorities and MPs got involved."

As the tabloids began to whip-up fear among the middle-classes, the political pressure began to grow to take action. And the events themselves were quickly taking on a more sinister edge.

Initially, the raves were organised by music promoters keen to make a fast few quid without troubling the taxman. But as the ticket money rolled in and the drug-taking increased, it was only a matter of time before the crooks started wanting in.

Organisers found themselves being threatened - or worse - into handing over cash for 'security'. One organiser found himself with a cocked gun resting on his temple until he, left with little choice, agreed.

"By then the villainy was getting involved and they were coming in with barrows full of drugs," says Tappenden.

"They would provide security. They were from the football hooligan gangs. They would sell the drugs outside the fences, and then confiscate it when the kids went inside so they could sell it again."

By now the police unit had outgrown Dartford and moved to Gravesend.

It had also harnessed the Home Office Large Major Enquiry System (Holmes) database - first used by police hunting the Yorkshire Ripper.

"We didn't get knives so much, but we were getting sawn-off shotguns and firearms..."

"In no time," explains Tappenden, "we had 1,700 vehicles with numbers, nearly 4,000 names and when we started to check it we realised a lot of them were villains. People with really nasty backgrounds.

"We didn't get knives so much, but we were getting sawn-off shotguns and firearms.

"The first organisers of the raves got frightened."

It was somewhat ironic that an underground movement so reliant on young people's desire to have a good time by using a drug which tended to spark feelings of euphoria, love and empathy should attract such violent individuals. But, as ever with the drugs trade, it proved rich pickings for the unscrupulous gangs.

Explains the former officer: "The youngsters who went were no trouble - they just wanted to party.

"At that stage it was a brand new phenomenon and they wanted to be part of it."

With pirate radio stations often used to broadcast the locations, Tappenden hatched on the idea of sending out 'false broadcasts' getting some of his younger team "who could talk the talk" to take to the airwaves imitating the likes of the station Sunrise.

"So we started splitting the parties up," he recalls.

"It became quite effective until there was a party being planned for Sevenoaks and our guys made out the party had been moved to Colchester. We knew everyone was on the M25 at the time.

"When they went to Colchester and couldn't find the party, they ransacked three petrol stations, looted them. I was the least popular man to the chief constable of Essex for a long time I can tell you."

Eventually, the political and media pressure became so intense a raft of new legal measures and powers were introduced to shut them down - allowing police to seize sound systems and limit numbers gathering.

The then-Home Secretary, Michael Howard, MP for Folkestone and Hythe, ushered in the Criminal Justice and Public Order Act 1994 and the wave of illegal outdoor events was over.

When Ken Tappenden retired from the force in 1992, he was even offered a job by one of the original rave organisers as they looked to go legal. He politely declined.

But he warns that the spate of outdoor parties which have sprung up in recent weeks make him anxious there could be a return.

"What we're seeing now is like a forerunner to what we had," he says.

"In recent weeks there have been parties in Hove, Sheerness and Vigo. They're using nitrous oxide now - leaving those silver cannisters everywhere. It's called hippy crack.

"They are ideal locations and gatherings for county lines drug gangs to infiltrate and then that will be really serious. Because they're pushing cocaine, heroin, sometimes amphetamine. They're not into soft drugs.

"And when they hook some of these young people, they won't unhook them.

"Today it's smaller scale, and a different motivation - caused by the lockdown to a degree - but it's something which excites young people again. "

Read more: All the latest news from Kent