How I Infiltrated The Secret Bunker Known As The UK's Area 51
Wednesday, 26th November 2025
This is the story of how I infiltrated one of Britain's most restricted Cold War bunkers, the site some call the UK's Area 51.
Over the years I've ended up on some unusual adventures, and this one is closely tied to the origins of my old website Nettleden.com - the project that eventually led me, unexpectedly, to Burlington, the vast underground city hidden beneath Corsham. What began as a day out with friends in 2002 slowly turned into a journey through Wiltshire's forgotten subterranean world, and ultimately the reason I was invited inside one of Britain's most secret Cold War sites.
The whole thing started on a warm, sunny Saturday in April 2002, when I headed out to Monkton Farleigh with three friends packed into my small, sky-blue Ford Fiesta. As we rolled through the village with the windows down, there were few hints about what was hidden beneath us.
I parked on the side of a quiet country lane and we walked down an old War Office access road that once served three of the site's entrances. The first entrance looked like a neglected agricultural shed, but it had once been a surface loading building. Inside, everything was empty and forgotten except for the concrete arch leading down to the bunker - bricked up at the top.
We carried on in the sunshine until we reached an almost identical building, another loading building. This one, to my surprise, hadn't been sealed. The slope shaft was open.
We weren't remotely prepared for an actual explore, but curiosity overruled common sense. With one tiny fading pocket torch between us, we descended the 135 steps into darkness, dropping about 30 metres below ground. At the bottom, the only light was our torch and the faint dot of the doorway we'd come through, a pinprick of daylight far above.
And then it opened out. A huge underground bunker stretched away in every direction, wide tunnels disappearing into blackness. It was obvious we weren't going to get far with a dying torch, so we reluctantly climbed all the way back up. But that summer, we went back again and again - we visited it to death.
As tends to happen with me, a new hobby quickly turned into a website. That's how Nettleden was born. People often ask where the name came from and whether it was anything to do with the village of the same name in Hertfordshire. It wasn't.
A few months earlier I'd seen the first 'Lord of the Rings' movie and, despite being boring as hell, it inspired me to build my own fantasy world online. I flicked through a road atlas looking for a suitable name for my virtual land and settled on the rustic-sounding Nettleden.
I never did build the kingdom of Nettleden, but when I needed an online home for documenting the very real fantasy world beneath Wiltshire, the ready-and-waiting Nettleden.com turned out to be the perfect place.
Monkton Farleigh was only the beginning. There was a whole subterranean network under Wiltshire waiting to be explored, and I found myself researching wartime bunkers during the week, then spending my weekends underground with a rotating gang of friends. I'd come home, sort through the photos, write everything up, and update the website.
Nettleden got attention - more than I expected. I made friends through it, many of whom are still some of my closest today. We explored together, and I even organised big yearly meet-ups where a huge group would gather for a BBQ in the Wiltshire countryside before heading underground.
I also picked up a bit of notoriety, which is strange because I'm not exactly a notorious person. It started when I put an image on the homepage...
Below it, I'd posted a call to arms encouraging people to "smash a wall down" to access a former WWII ammunition store.
Now, in my defence I was young, naive, and it was a stupid idea. We'd explored this particular bunker a few times, then one day someone built a very solid wall to keep people out. I wrongly felt entitled to go inside. I didn't even seem to grasp that the wall had been paid for by the site's actual owners.
Looking back, of course it was ridiculous. Everywhere belongs to someone, and in this case the owner already ran a secure storage company next door and planned to expand into the space we'd been treating as a playground.
Unsurprisingly, this earned me a bad reputation with other underground explorers. I wasn't going to knock anything down - I didn't even own a hammer, let alone a battery-powered circular saw - but I was annoyed it had been blocked off.
Eventually the drama died down and Nettleden evolved. What started as flat HTML soon became a site built with SSI, which felt futuristic at the time.
In late 2003, a BBC journalist called Dylan Winter got in touch. He was making a Radio 4 documentary called Subterranean Stories, which also featured local historian and author Nick McCamley. In the documentary that aired in 2004, Dylan told his listeners, "I've been looking on the web and I've found a group of people who Nick would find very irresponsible. They call themselves urban explorers."
We met him on location in Wiltshire to record the programme. At one point we were stood in front of a bricked-up bunker entrance. Dylan set the scene for the listener: "Here in front of us is a curved arch and then in the middle, it's been bricked up with breeze blocks. You want to get through that wall, don't you?"
I told him, "I just think it's a shame that something that has that much history and played such a big part in the war, is bricked up and closed off to the public."
After that, public opinion towards me softened. By 2005, I was appearing on local radio as: "Steve Higgins is an underground building enthusiast."
When the Ministry of Defence (MOD) put Burlington - the enormous underground city beneath Corsham - up for sale, the local station GWR interviewed me about what could be done with it. The news report used a short sound bite where I told listeners, 'The nicest thing that could happen to it would ideally be a museum, but I don't think cost-wise that would ever work out. A lot of the other Corsham quarries have been used for underground storage, either wine or probably secure documents is the most likely.'
If I was ever going to be known for anything, it would be underground exploration. I had more media attention for this strange hobby than for anything else I've done. The BBC wrote about me, The Guardian ran a full-page spread, and The Times published a feature that introduced me as "Urban explorer Steve Higgins avoids anti-trespass barriers and bats to descend into one of the abandoned tunnels near Bath that even people living nearby barely know exists."
In 2006, BBC Radio Wiltshire invited me in for an interview - conducted, bizarrely, in the underground car park to make it feel more "authentic."
The presenter, Will Walder, opened with his first question, "what does it smell like down here?"
I didn't know what to say, so I replied, truthfully, "Petrol."
After the awkward laugh, Will asked how I got started exploring in the first place. I explained, "Just because it was different, it's just something people don't see. And there's so much history tied in with the places. It's forgotten history really."
By then, Nettleden had grown into a PHP and MySQL-driven site with user accounts, comments, photo uploads, and community contributions. We'd visited dozens of underground locations across Wiltshire, but one place remained completely inaccessible... Burlington.
Eventually, I caught the attention of the MOD. Someone who worked there reached out, and we met for drinks to talk about Corsham's underground secrets. Walking into that pub felt like the set-up for a sting operation, but he turned out to be a friendly older man nearing retirement, with a lifetime of knowledge to share.
A few months later, he invited me to visit him at work.
And that's how I infiltrated the UK's answer to Area 51 - not by climbing fences or smashing walls, but by running a website that caught the right person's eye.
We spent a whole day underground. We were allowed to take photos and video, but my gear back then was nothing like what I use today. All I've got left are shaky, low-resolution memories.
Nettleden ran for a few more years, but eventually it was overtaken by Higgypop Paranormal. Once it passed its peak, it didn't make sense to maintain the site separately, so I merged the content into Higgypop. All of my underground content still exists on a dedicated section of the website.
My years working on Nettleden and the adventures it led me on also inspired my first book, 'Hidden, Forbidden & Off-Limits', which tells the story of my experiences underground and the people I met along the way.
Over the years I've ended up on some unusual adventures, and this one is closely tied to the origins of my old website Nettleden.com - the project that eventually led me, unexpectedly, to Burlington, the vast underground city hidden beneath Corsham. What began as a day out with friends in 2002 slowly turned into a journey through Wiltshire's forgotten subterranean world, and ultimately the reason I was invited inside one of Britain's most secret Cold War sites.
The whole thing started on a warm, sunny Saturday in April 2002, when I headed out to Monkton Farleigh with three friends packed into my small, sky-blue Ford Fiesta. As we rolled through the village with the windows down, there were few hints about what was hidden beneath us.
I parked on the side of a quiet country lane and we walked down an old War Office access road that once served three of the site's entrances. The first entrance looked like a neglected agricultural shed, but it had once been a surface loading building. Inside, everything was empty and forgotten except for the concrete arch leading down to the bunker - bricked up at the top.
We carried on in the sunshine until we reached an almost identical building, another loading building. This one, to my surprise, hadn't been sealed. The slope shaft was open.
We weren't remotely prepared for an actual explore, but curiosity overruled common sense. With one tiny fading pocket torch between us, we descended the 135 steps into darkness, dropping about 30 metres below ground. At the bottom, the only light was our torch and the faint dot of the doorway we'd come through, a pinprick of daylight far above.
And then it opened out. A huge underground bunker stretched away in every direction, wide tunnels disappearing into blackness. It was obvious we weren't going to get far with a dying torch, so we reluctantly climbed all the way back up. But that summer, we went back again and again - we visited it to death.
As tends to happen with me, a new hobby quickly turned into a website. That's how Nettleden was born. People often ask where the name came from and whether it was anything to do with the village of the same name in Hertfordshire. It wasn't.
A few months earlier I'd seen the first 'Lord of the Rings' movie and, despite being boring as hell, it inspired me to build my own fantasy world online. I flicked through a road atlas looking for a suitable name for my virtual land and settled on the rustic-sounding Nettleden.
I never did build the kingdom of Nettleden, but when I needed an online home for documenting the very real fantasy world beneath Wiltshire, the ready-and-waiting Nettleden.com turned out to be the perfect place.
Monkton Farleigh was only the beginning. There was a whole subterranean network under Wiltshire waiting to be explored, and I found myself researching wartime bunkers during the week, then spending my weekends underground with a rotating gang of friends. I'd come home, sort through the photos, write everything up, and update the website.
Nettleden got attention - more than I expected. I made friends through it, many of whom are still some of my closest today. We explored together, and I even organised big yearly meet-ups where a huge group would gather for a BBQ in the Wiltshire countryside before heading underground.
I also picked up a bit of notoriety, which is strange because I'm not exactly a notorious person. It started when I put an image on the homepage...
Below it, I'd posted a call to arms encouraging people to "smash a wall down" to access a former WWII ammunition store.
Now, in my defence I was young, naive, and it was a stupid idea. We'd explored this particular bunker a few times, then one day someone built a very solid wall to keep people out. I wrongly felt entitled to go inside. I didn't even seem to grasp that the wall had been paid for by the site's actual owners.
Looking back, of course it was ridiculous. Everywhere belongs to someone, and in this case the owner already ran a secure storage company next door and planned to expand into the space we'd been treating as a playground.
Unsurprisingly, this earned me a bad reputation with other underground explorers. I wasn't going to knock anything down - I didn't even own a hammer, let alone a battery-powered circular saw - but I was annoyed it had been blocked off.
Eventually the drama died down and Nettleden evolved. What started as flat HTML soon became a site built with SSI, which felt futuristic at the time.
In late 2003, a BBC journalist called Dylan Winter got in touch. He was making a Radio 4 documentary called Subterranean Stories, which also featured local historian and author Nick McCamley. In the documentary that aired in 2004, Dylan told his listeners, "I've been looking on the web and I've found a group of people who Nick would find very irresponsible. They call themselves urban explorers."
We met him on location in Wiltshire to record the programme. At one point we were stood in front of a bricked-up bunker entrance. Dylan set the scene for the listener: "Here in front of us is a curved arch and then in the middle, it's been bricked up with breeze blocks. You want to get through that wall, don't you?"
I told him, "I just think it's a shame that something that has that much history and played such a big part in the war, is bricked up and closed off to the public."
After that, public opinion towards me softened. By 2005, I was appearing on local radio as: "Steve Higgins is an underground building enthusiast."
When the Ministry of Defence (MOD) put Burlington - the enormous underground city beneath Corsham - up for sale, the local station GWR interviewed me about what could be done with it. The news report used a short sound bite where I told listeners, 'The nicest thing that could happen to it would ideally be a museum, but I don't think cost-wise that would ever work out. A lot of the other Corsham quarries have been used for underground storage, either wine or probably secure documents is the most likely.'
If I was ever going to be known for anything, it would be underground exploration. I had more media attention for this strange hobby than for anything else I've done. The BBC wrote about me, The Guardian ran a full-page spread, and The Times published a feature that introduced me as "Urban explorer Steve Higgins avoids anti-trespass barriers and bats to descend into one of the abandoned tunnels near Bath that even people living nearby barely know exists."
In 2006, BBC Radio Wiltshire invited me in for an interview - conducted, bizarrely, in the underground car park to make it feel more "authentic."
The presenter, Will Walder, opened with his first question, "what does it smell like down here?"
I didn't know what to say, so I replied, truthfully, "Petrol."
After the awkward laugh, Will asked how I got started exploring in the first place. I explained, "Just because it was different, it's just something people don't see. And there's so much history tied in with the places. It's forgotten history really."
By then, Nettleden had grown into a PHP and MySQL-driven site with user accounts, comments, photo uploads, and community contributions. We'd visited dozens of underground locations across Wiltshire, but one place remained completely inaccessible... Burlington.
Eventually, I caught the attention of the MOD. Someone who worked there reached out, and we met for drinks to talk about Corsham's underground secrets. Walking into that pub felt like the set-up for a sting operation, but he turned out to be a friendly older man nearing retirement, with a lifetime of knowledge to share.
A few months later, he invited me to visit him at work.
And that's how I infiltrated the UK's answer to Area 51 - not by climbing fences or smashing walls, but by running a website that caught the right person's eye.
We spent a whole day underground. We were allowed to take photos and video, but my gear back then was nothing like what I use today. All I've got left are shaky, low-resolution memories.
Nettleden ran for a few more years, but eventually it was overtaken by Higgypop Paranormal. Once it passed its peak, it didn't make sense to maintain the site separately, so I merged the content into Higgypop. All of my underground content still exists on a dedicated section of the website.
My years working on Nettleden and the adventures it led me on also inspired my first book, 'Hidden, Forbidden & Off-Limits', which tells the story of my experiences underground and the people I met along the way.