Updated: Jul 26, 2021
A Rather Curious Discovery
In 1780, local builders were laying the foundations for a house along Blackheath Hill. There was nothing strange about their digging (or their day) until they stumbled across a rather curious entrance that led them to what lurked beneath.
The mysterious caverns extended underground by several hundred feet, with the initial entrance through a narrow hole.
The cavern’s rooms were described in 1818 by Mr Edwards, a topographer [person who describes the surface features of a place or region], as irregular in shape, ranging from twelve to thirty-six feet wide (one was about thirty by sixty feet). One of the rooms had a large conical dome, thirty-six feet high and forty-three yards in circumference, supported by chalk columns.
The caverns consisted ‘of four irregular apartments, in the furthest of which is a well of pure water, twenty-seven feet in depth. They [were] cut out of a stratum of chalk and flint and communicate by small avenues; the bottom of the cavern is sand.’
Realising the earning potential of such a discovery, the tenant of Cavern Cottage, whose garden the entrance was in, charged sixpence per person to take visitors down into the rooms. It was a nice little earner for him until 19-year-old Lucy Talbot, overcome by noxious fumes, was carried out into the open air while fainting. Lucy sadly died shortly afterward.
Not deterred by such a tragedy, the tenant of Cavern Cottage cut a ventilation shaft into the caverns and added a pair of bellows to circulate fresh air.
The earlier patrons to visit these curious caverns appeared to have been highly respectable.
‘The walls of the main cavern [were] covered with inscriptions, chiefly names, and dates, and the oldest date [was] 1780, when, many think, the Blackheath caverns were first discovered. The name of Sir Robert Peel was found among these inscribed on the chalk walls.’ Even fine young ladies found the caverns a delight to visit – an adventure in the underground depths near Greenwich’s royal history.
But things soon changed, and the caverns became a place for some raucous underground activity. Parties began to happen. A chandelier was hung from the roof, and a bar was built in the corner of the largest cavern.
During the nineteenth century, these curious underground rooms became a popular nighttime venue for entertainment. The entrance fee was around six shillings for the public to take a torch down and enjoy the bar, chandelier, and ventilation.
Drinking parties and balls made the Blackheath caverns the place to be. In November 1846, they were transformed into a ‘capacious ball room capable of holding fifteen hundred people.’ But despite the excitement, the ball was cut short due to poor ventilation (again).
There were lurid stories of unclothed female dancers, and, according to rumours, the gatherings rapidly got out of hand. Legend has it that the local council were grieved by the lurid activities underground, and in 1854 the caverns were sealed up.
Whether or not the caverns were closed due to wild debauched villagers and visitors having the time of their life is an unknown. Maybe they were just considered unsafe.
Potential Air-raid Shelter
In 1938, the caverns were assessed for use as a pre-made air-raid shelter during the war. It was estimated that they could hold around 1,500 people at any one time.
'An entrance to the Blackheath caverns has been found in the back garden of a house at Maidenstone Hill. It was known that these caverns existed, and local officials have been searching for the entrance for some time. The entrance was found after a search by a diviner and by an electrical resistance survey. The Greenwich Borough Council will now consider whether to adapt the caverns for use as air-raid shelters. Council workmen sank a shaft some 40 ft. deep in the garden, and it was found that fallen material had blocked the original entrance tunnel.
The caverns appear to be exactly as they were left when they were closed in 1853 because they were considered unsafe. The remains of a stone and brick-built bar is another object of interest. On the top of it and covering the floor all round were pieces of broken bottles, and it is suggested that the place was at one time used as a ballroom.’
Deemed unsafe, the caverns were closed again and have remained so ever since.
The Origins and History of the Blackheath Caverns
Saxons and Deneholes
According to Pinnock’s Guide to Knowledge, ‘The origins of the caves is not known, nor do we find anything but conjecture about them in the old books on antiquities. They are no doubt very ancient and perhaps were excavated by the Saxons. The fact that wherever these chalk caves exist, there has always been some engagement between the Danes and the Saxons would seem to favour the idea that they were places of refuge from the fierce Dane.
There is speculation that the caverns were known of as far back as AD 450, during the time of Hengist, King of Kent, although the theory might be stretching it a bit. Hengist (the first Saxon King of Kent) met with some angry sword-wielding Britons near Crayford (Crecanford) in 457 and killed a lot of them – 4,000 men and four commanders – apparently. Many of the chalk excavations around Crayford are similar to the caverns under Blackheath.
Evidently, ‘[the Saxons] used to dig certain caves under the ground, that when the enemy came and spoiled all that was around them, such things as were thus hidden either lay unknown or by this very means deceived him who sought after them.’
‘It seems probable that they have, at some distant period, been used as a place of concealment, and the general supposition is that it was used for that purpose during the Saxon and Danish contests, but nothing has been discovered to assist inquiry.’
It was thought for some time that the caves were Dane Holes due to the spelling of deneholes, but dene in Saxon language meant den, which supports the idea that the caverns were used to hide from the pillaging Danes when they came and ransacked our lands (and our village).
It seems the novelty of the underground rooms wore off in the nineteenth century and Essex became more interesting. So that was the end of that – for a while.
In 1677, William Steers was fined £40 for mining underneath Blackheath Hill, which caused wagons to overturn. There’s a lot of speculation that the caverns were created by chalk mining because the area is rich with it. There are also historical accounts of other chalk mines in the area, but in 1882, an archaeologist named Spurrell, after much closer inspection, writes that the caverns were too ‘clayey’ and too ‘deep’ to be just chalk mines in their origin. Spurrell classed them as ancient pits.
It’s possible that Jack Cade, the treacherous traitor and insolent rebel, may have hidden in the Blackheath Caverns. They were, after all, given his name back in the nineteenth century. Cade camped out in Blackheath on a couple of occasions, along with thousands of his men, for various traitorous deeds. He needed somewhere to hide, and the caverns were big enough for Cade and his men to hide within them.
Blackheath, Greenwich, and its surrounding areas have been prone to sinkholes, and there has, over the years, been lots of speculation as to why they have happened. Kidbrooke experience such a bad one in 1798 that it swallowed a horse – whole.
April 1878 – On the west side, from Greenwich Park to Blackheath Station and from the park to the Paragon, a subsidence near the row known as Rotten Row appeared in the early morning. The hole was 8 or 9 yards in circumference.
November 1880 – another hole appeared near the gravel pit below Eliot Place and about 550 yards southwest of the first hole. Later in the same month, a third subsidence made its appearance, this time about one hundred yards to the southeast of the first subsidence, and nearer to All Saints.
July 2002 – A sinkhole appeared on the A2, near to where the caverns are thought to be.
Is there more to the caverns?
In short, yes! There is so much more to discover and learn. Primary sources are hidden in the depths of archives and new information is coming to light all the time as local historians and researchers wade through the facts and embellishments of history.
One of the best sources for more detailed information (probably the best, actually) is The Subterranean Greenwich and Kent website. The research they do is detailed, thorough and always update. You can check them out here.
Where are they?
The image below shows where the caverns are (top left) along Blackheath Hill and Maidenstone Hill. Credit must be given to Subterranean Greenwich and Kent for sharing the map on their website (they really are worth checking out), and also to the London Borough of Greenwich.
 Hart, F. H. (1971). History of Lee and its neighbourhood. London: Conway Maritime Press.
 Hart, F. H. (1971). History of Lee and its neighbourhood. London: Conway Maritime Press. The Times, October 27, 1939 p.5
 Instructive Rambles in London and Adjacent Villages: Designed to amuse the mind, and improve the understanding of youth. Helme, Elizabeth, 1800, London: T.N. Longman, and O. Rees, Paternoster Row; and E. Newbery, ST. Paul’s Church-Yard, 1800. p.165
 The London Pocket Companion by Jo Swinnerton [London]: Pavilion, 2008
 Rochester and Chatham Standard, & Gravesend and Milton Express, Saturday, November 7, 1846.
 From The Times, October 27, 1939 p.5
 Pinnock, W., Gilbert, J. Burkhart., Edwards, W. (183318321839). The guide to knowledge. London: Printed for the proprietor; and published by W. Edwards .... p.682
 The Kentish Independent Saturday, May 18, 1850, p.5
 Tacitus de Moribus Germanorum p.620
 Richardson, H. S. (1834). Greenwich: its history, antiquities, improvements, and public buildings. London: Simpkin & Marshall; [etc., etc.].
 Meetings of Antiquarian Societies. The Antiquary; Jun 1881; 3, pg. 273