Coulsdon Deep Shelter - November 2024
Facing some inevitable downtime after a shoulder operation, I found myself with time to finally go through photos from an explore a few months back: Coulsdon Deep Shelter. I know it’s been absolutely done to death, which is why I initially held back on a report, and honestly, my first look at the pictures wasn't inspiring. Mostly thanks to the state it's in now and poor lighting conditions. However, following in the footsteps of a great report by @The_Raw where the vandalism has been removed digitally I decided to remove much of the vandalism that's accumulated over the years in the shelter. Consider this my take on the well-worn classic, showing both the current sad reality of the site and, using some editing magic to peel back the layers of spray to reveal the history underneath.
Explore
Coulsdon had been on the list for a while, with no particular rush to go explore it and getting passed up for more interesting sites. Eventually on an icy cold mid November afternoon I decided to finally cross it off. Despite having coordinates to the site finding a way in wasn't immediately evident due to the spotty reception and it took a bit of searching around before we succesfully located a route down into the darkness.
Dropping inside, the chill hit, along with the realisation as to why I had held off on this site for so long: it was completely trashed. There was that grim smell of old ash hanging in the air from past goons who had undoubtedly attempted to set light to the site. Pretty much every wall was plastered in graffiti and the floors were thoroughly littered with discarded beer cans. You could tell this was the kind of place that had seen a lot of history, but also a fair share of idiots.
Despite the mess, we could still spot interesting bits left over from the shelter's past lives such as old lens equipment and discarded car parts. All in all we spent two hours in the shelter exploring every passageway and goofing about. Definitely glad to have finally seen it and ticked it off the list, even in its current battered state.
History
Construction & Wartime Use
AI rendition of Cane Hill Asylum during wartime
AI rendition of Cane Hill Asylum during wartime
During the Second World War, Surrey Council planned several deep public shelters, including one beneath the grounds of Cane Hill Asylum in Coulsdon (Shelter No. 4). Although designed by Surrey's Highways and Bridges department, records indicate ownership rested with London County Council. The initial ambitious plans from circa 1940 detailed three parallel tunnels connected by four cross-passages, along with facilities like a sick bay and canteen. However, encountering chalk during construction meant only two main tunnels and two cross-passages were completed, significantly reducing the intended capacity to 720 people and areas such as the canteen were cancelled.
Designed primarily for local civilians needing refuge, the shelter's actual wartime occupancy remains unclear. Coulsdon avoided the heaviest bombing, and many residents had private shelters, suggesting potential underutilisation. Intriguingly, the later discovery of wartime Berlin reconnaissance photographs within the tunnels gives weight to persistent rumours of undocumented use by the Canadian Military, possibly for storage, alongside civilian sheltering.
Post-War Adaptation: Optics in the Underworld
After the war, following brief consideration as a potential Cold War nuclear shelter, the tunnels quickly found a new role. In 1949, Cox, Hargreaves & Thomson Ltd. moved in, recognising the site's unique advantages for manufacturing large, high-precision telescope lenses. The deep tunnels offered an exceptionally stable year-round temperature (around 12°C / 54°F), vital for preventing glass distortion during grinding and polishing. Equally important, the long, straight passages were perfect for testing the focus of these large optics.
The company made considerable adaptations, modifying entrances, reinforcing areas, installing modern wiring and lighting, and bringing in specialised French machinery – operations captured in a 1960 British Pathe newsreel. However, working conditions remained arduous due to the constant cold and damp, which frequently caused electrical faults. A notably resourceful solution involved modifying a refrigerator to act as a dehumidifier, collecting moisture from the air – a device which we came across but didn't have the foresight to capture. Despite producing high-quality lenses, the challenging environment proved to be too much with the company ceasing operations there in the mid-1970s.
Decline
An engine that has been dumped in the shelter
An engine that has been dumped in the shelter
The shelter's post-industrial life was short-lived. A subsequent attempt to use the space for garage storage quickly failed, as the pervasive damp caused inescapable problems with rust. Thereafter, the tunnels unfortunately became an unofficial dumping ground, with remnants of items like old telephone boxes and tractor parts testifying to this period. This dereliction prompted the council to seal the entrances with earth banks in the 1980s. This closure, however, wasn't final. Over the following decades, the site became subject to a cycle of being sealed and then re-accessed by locals and other explorers. Today, escaping the demolition of Cane Hill asylum the Coulsdon Deep Shelter lies abandoned and in disrepair, marked by graffiti and lacking formal heritage protection.
Photographs
For the cleaned up photos I've decided to use a table to showcase a before and after, the before for accuracy sake and after for general viewing pleasure. Other photos that did not require reparations have been left in a standard format. Despite the removal taking a goof chunk of time in the end it was well worth it.
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Looking down a tunnel where the chalk wall can be seen at the end. Some iconic graffiti has been left.
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Peeling back layers of graffiti on a selfie.
An electrical system which has succumbed to rust.
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A lens polishing machine where large optics would've been manufactured; the rusted units demonstrating why operation ceased.
Vent from some machinery? Unsure.
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Brick wall smashed down to allow access into the system.
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A blast proof door still standing after all these years.
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A doorway likely serving as a partition during the Lens making era of the shelter.
Remnants of a chair that was likely dumped many decades ago.
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An axle from a tractor that was dumped down the shelter.
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Some more digital clean up of a view down the tunnel.
Cogs left over from some long gone machinery/car
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Once cleaned up the brickwork is rather beautiful.
Thanks for reading
Thanks for reading
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