What I learnt on a tour of the M25 on its 40th birthday

In the fast lane of the M25, I get an idea of what it might be like to be famous. A man in a van honks at me appreciatively as I overtake. A guy in a Range Rover gives me the thumbs up. I’m even filmed by the female passenger of a BMW. Only it’s not me they’re fawning over, it’s the car I’m driving.

I’m doing a lap of the M25 to mark its 40th anniversary. I usually approach the London Orbital with the same enthusiasm as I do my tax return; it’s a necessary evil, a means to an end. But today’s different. Today, I’ve hired a Sierra Cosworth for the journey – and the M25 is my destination. I’m hoping this iconic car, with its ridiculous whale-tail spoiler and Porsche-bothering acceleration, will help me unravel some of the stories behind this road, and reveal what they say about Britain.

The “Cossie” was unleashed on to our roads the year the M25 was completed. You might ask why I didn’t hire the classier Jaguar XJ40 or more refined Rover 800, which also came out in 1986. But nothing on four wheels epitomised Margaret Thatcher’s aspirational, up-by-the-bootstraps late-1980s era like the Cosworth.

“It was a blue-collar supercar,” says its owner Lee Lambert, a Millwall-supporting south-east Londoner, joining me for a few junctions. “It gave the working classes something that some people thought they shouldn’t have.” Power.

An absolutely bonkers amount of power. Putting your foot down in this is like firing a gun; it’s all I can do to hold on as we bear down on the Dartford Crossing, Canary Wharf glistening in the distance.

Thatcher cut the ribbon on the M25 on October 29 1986, two days after the “Big Bang” turned London into a global financial centre. This wave of deregulation sparked a scramble for talent and the East End’s gift-of-the-gab market traders, or “barrow boys”, made excellent brokers. It was out with fingerless gloves, in with pinstripe suits.

What Thatcher saw in the M25 was a solution to London’s congestion problem. What the city’s upwardly mobile young men saw was a 117-mile racetrack for their new playthings. It was a great era for motors, defined by the likes of the BMW M3, Porsche 911 Turbo (“the widow maker”), and Cossie, which was a favourite in Ford Land. You can take the boy out of Dagenham…

The Sierra purrs as we pass the site of the old Dartford Crossing toll booths, the racetrack’s unofficial start-finish line. Time-stamped tickets issued here were handy proof of a sub-one-hour lap of the motorway (that’s an average of at least 117mph!) and, thus, admission to the fabled “M25 Club”.

“You could belt around it in those days, there were no cameras,” says Lambert, tutting. “Now they’re everywhere.”

Lights dance over the Sierra’s bonnet as we descend into the tunnel. A sunny Essex greets us on the other side. This was the spiritual home of the Cossie. Many ended up on its driveways. Few stayed on them.

“They were notoriously easy to steal – you just needed a screwdriver,” says Lambert, a courier. “Villains used to nick them for robberies.” And the M25 was their escape route.

The motorway had another unintended consequence: it supercharged the rave scene. Bridges and M25-adjacent warehouses were perfect spots for illegal acid house parties. So influential was the motorway on dance culture that one electronic group took on its name: Orbital.

Nuclear Armageddon

The idea for a ring road around London was first mooted in 1905, but it wasn’t until 1973 that spades entered the ground. Even as bulldozers moved in, there was a lingering fear that the whole project could disappear in a big mushroom cloud along with the rest of civilisation.

I peel off at junction 28, driving through Brentwood, following country lanes through reddening woodlands, past gated mansions and fly-tipped lay-bys. Soon, I arrive at what looks like a suburban bungalow plonked in a wood. “Welcome to Britain’s hidden history,” reads a sign.

I’m at Kelvedon Hatch Secret Nuclear Bunker. Had the Cold War turned hot, this is where London would have been governed from. Thatcher would have hunkered down here, along with top officials, engineers and scientists.

“There would have been around 450 people here,” says Mike Parrish, the bunker’s owner. “No members of the public, obviously – they would have been out there dying under their kitchen tables.”

The bungalow is the unassuming entry point to a subterranean survival complex.

“It’s like a Norman castle buried under 30ft of dirt,” says Parrish, leading me along a maze of corridors, past offices filled with old computers, through dingy dormitories and a clinic that smells of TCP. We arrive at a room marked “Prime Minister”, where a mannequin of Thatcher is tucked up in bed.

Kelvedon Hatch was one of 18 nuclear bunkers built in Cold War Britain. They were decommissioned in 1992 after “Maggie decided the Russians were our friends,” says Parrish, whose laconic wit adds levity to what’s easily the M25’s most fascinating and disturbing attraction.

Pitstop pianist

Back on the motorway, the daily migrations of its motorists seem trivial against the apocalyptic vision I glimpsed at the bunker. On the radio, they’re talking about another world-ending threat: rogue AI. I switch it off and get back into the Eighties spirit with some Duran Duran.

The “world’s biggest car park” soon lives up to its nickname. The M25 was designed to carry 100,000 vehicles daily, but is used by more than double that today. Some sections had a fourth lane added to ease congestion, but people can’t handle four. Three is easy: slow, medium, fast. Four confuses them. Most hang on idiotically in the second lane.

I get going again at Bell Common Tunnel, which roars under a cricket pitch, before peeling off at junction 25 for Crews Hill Vintage Emporium – the antithesis of boring service stations.

“I remember the M25 opening,” says Mike Martin, an antiques dealer with a 1930s Telegraph sign in his stall. “It was gridlocked on the first day,” he laughs.

Like the Sierra, the emporium makes me nostalgic for the past. I lose myself in its stalls, fascinated by the juxtaposition of stuffed owls and decommissioned ammunition, 1980s pornography and a book about the Third Reich.

Back on the road, I roar past Waltham Abbey Cemetery, peeling off again at South Mimms, the M25’s first service station (today there are four, with Clacket Lane, Cobham and Thurrock completing the quartet). Most people come to this anonymous Hertfordshire pit stop out of necessity. Not Alex Malkov, who’s tickling the ivories on the public piano when I walk in.

“I come just to play this,” says the Russian musician. “I don’t have room for a piano at home, so I go to service stations to play theirs. I’m going up the M1 after this.”

As Lambert did earlier with the Cosworth’s bonnet, Malkov pops the piano’s hood, proudly showing me the bits he repaired. “It was in a bad way when I came,” says the London-based app developer. “Nobody really looks after them.” He plays me the score from an old Russian film which is still in my ear when I rejoin the M25.

The road to hell

More traffic presents an opportunity to ponder some of the motorway’s mysteries. Who is tagger “10FOOT”? What’s with all the abandoned shoes? And who in their right mind would go on an M25 coach tour?

Incredibly, one existed – briefly – in 2012, only it never took off. It was a tall order to expect people to pay to sit in slow-moving traffic, which is what I do for most of the western edge of the M25, the busiest section of motorway in Britain, creeping through Buckinghamshire and Berkshire as planes descend on Heathrow.

The motorway loosens up again along its most scenic stretch, through the North Downs in Surrey and Kent, but I’m jaded. I’ve had enough of the M25 and its maddening traffic. The Sierra is thrilling, an actual workout, but it’s a reminder too of how dreary and sanitised motoring has become.

Exiting the motorway one last time, I wrap up my tour in the George & Dragon, a low-beamed 16th-century pub in chocolate-box Chipstead that was just about spared by the M25.

I sit in the beer garden admiring the Sierra. Within a year of its launch, the Cossie had become uninsurable, too hot for underwriters to handle. London, too, had gone from boom to bust as the Big Bang of 1986 was followed by 1987’s Black Monday. As for the M25, far from being a solution to congestion, it just added to it.

“This ain’t no upwardly mobile freeway,” Chris Rea crooned in 1989. “This is the road to hell.”

He was wrong. The M25 goes nowhere. It’s a loop, liminal and transient, littered with lost shoes and legends; London’s dirty bubble. And on it roars in the near-distance, as people gather around the Sierra, reminiscing about the old days.

Gavin Haines rented the Sierra Cosworth through Spoke Hire, a platform for peer-to-peer classic car hire.

Try full access to The Telegraph free today. Unlock their award-winning website and essential news app, plus useful tools and expert guides for your money, health and holidays.