T H E   D E R E L I C T   M I S C E L L A N Y

Once the stuff of a rich local mythology involving underground mortuaries, secret medical experiments and nuclear paranoia, the mysterious tunnels below what was Cane Hill Hospital in Coulsdon have recently been the subject of much research which has grounded them firmly in established fact - some would say this takes something away from them, but to me the history is nearly as interesting as the myth.

I've been wanting to go to the tunnels for as long as I've known about them. Actually, what I really wanted to do was visit Cane Hill itself, the brooding Victorian asylum which imprinted itself so deeply on the local psyche for so many years, and which through photos posted on 'urban exploration' websites, inspired my early adventures creeping around derelict and decaying buildings. ...I wanted to, but I missed it - demolished before I got around to making the trip. As it happens though, the tunnels have little to do with the old hospital, at least directly. They are a destination in their own right, dark, cavernous and disorientating, full of subterranean rumblings and the slow drip of water percolated through chalk above.

Main entrance, partially blocked Original blast door still in situ. Main tunnel looking back towards the entrance. Main tunnel viewed from near the entrance. The recess on the right contains switchgear. Open area at the end of the first transverse tunnel. The original purpose of this room is unknown; it is marked 'sick bay' on early plans made by Cox, Hargreaves and Thomson, but later housed a large lens grinding machine. Latrines in first transverse tunnel. Latrines. Dead-end tunnel with lens-grinding machine. Southern tunnel with post-war divider. Southern tunnel - vintage tractor wheels. Southern tunnel - storage racks. Sketch plan from exploration journals, December 2017

The Brighton Road Deep Shelter was built by Surrey County Council at the start of the Second World War to protect the population of Coulsdon who did not have access to their own air raid shelters. It is not recorded exactly when the tunnels were excavated but a larger complex at Epsom was constructed c.1941 on a very similar plan. The complex comprised three parallel tunnels driven into the hillside with two interconnecting tunnels (it is likely that the original plan had called for four, but two were never completed) between them. Spoil from the diggings was piled in a large bank in front of the three offset entrances to provide blast protection. There is little known about the wartime use of the shelter, and it has been suggested that it was actually taken over by the Canadian Military (who were very active in this part of Surrey) during the latter part of the war. The shelter was resurveyed post-war as a potential fallout shelter, either for civillian or more likely strategic purposes. Ultimately, nothing came of this and the tunnels were put up for sale.

In 1949, Coulsdon Deep Shelter found novel use as the manufacturing facility of Cox, Hargreaves and Thomson L^td, who made lenses for telescopes, cine-cameras and other precision optics. The facility's constant 54℉ (23.3℃) without detectable variation throughout the year meant that the glass would not expand or contract, while the long, straight tunnels proved ideal for test focussing.

The underground factory remained in use for nearly thirty years, despite being by all accounts a rather unpleasant place to work - close, damp and without any daylight. Electrical failures were common - a result of moisture condensing inside the fuse boxes - and the machinery was prone to corrosion until a primitive dehumidifier was improvised from a rewired refrigerator. The factory closed in the mid 1970s and the company was wound up in 1978. After this, the tunnels were used as storage for a garage and then as a dumping ground for all manner of junk before being sealed in the 1980s. It wasn't until the a couple of decades later that access again became possible, and since then there has been a war of attrition between the landowner, who keeps sealing up the entrance, and the local youth, who keep digging it out again.