Has The Folkestone Leas Lift Company Created The Perfect Conditions For Another Landslide To Come.
Has The Folkestone Leas Lift Company Created The Perfect Conditions For Another Landslide To Come?
As you are all aware, I have covered landslides and the part tall heavy trees sitting on the cliff face summit along the whole of the Leas escarpment many times these past 10 months. I raised these issues with FHDC over many emails and 2 site meetings with Councillor Speakman before most of the landslides took place. I warned the council that the height and weight of at least half a dozen trees on the Zig Zag path threatened the path with a future catastrophic collapse, which could render the path out of operation for many months, perhaps years, perhaps forever.
The 1784 Leas landslide in Folkestone was primarily caused by a combination of heavy, sustained rainfall and the area's unstable coastal geology. Rainwater seeped into the weakly cemented sandstone and chalk, adding weight while lubricating the underlying clay, which ultimately caused the cliff face to give way toward the sea.
This is what geologists know and remember: we have no real account of what happened, no photographs, as this event occurred long before the invention of the camera and photographs. As far as I know, this is the only sketch there is of what Folkestone's new shoreline looked like after the landslide done by the. Rev John Lyon below.
While contemporary descriptions from the era, such as the account by the Rev. John Lyon published by the Royal Society, documented it as a "subsidence of the ground," modern engineering geology attributes the massive failure to several interconnected factors.
1. Weak and Unstable Geological Composition
The cliffs along the Leas are structurally precarious due to the way different rock layers sit on top of one another:
- The Folkestone Formation: The upper part of the cliff consists of loose, medium-to-coarse sands and weakly cemented sandstones. It is highly porous and lacks structural cohesion.
- The Gault Clay Bed: This sand sits on top of a deep, thick layer of slick Gault Clay. Clay is completely impermeable, meaning water cannot drain through it.
2. High Groundwater Pressure and Lubrication
Landslides along this stretch of coast historically peak during the winter months when groundwater levels surge.
- The "Slip" Plane: When heavy rain or winter storms hit Folkestone, water drains rapidly straight through the porous upper sandstone until it hits the impermeable Gault Clay.
- The Lubrication Effect: Unable to escape, the water pools at the boundary layer, building up immense hydrostatic pressure. This completely lubricates the boundary, turning the top of the clay bed into a slick slide for the massive weight of the cliff above.
3. Marine Erosion and Toe-Weight Removal
The English Channel acted as a catalyst at the base of the cliff:
- Wave Action: Waves constantly battered the foot of the cliffs, undercutting the soft clay at the bottom.
- Loss of Support: By washing away the debris and shingle at the bottom (known as the "toe" of the slope), the sea effectively stripped away the natural, heavy weight holding the hillside back. Without that counterbalancing weight, gravity easily pulled the weakened cliff down.
The Lasting Impact
Instead of dropping straight down, the cliff experienced a massive rotational failure, meaning the ground slid forward and tilted backwards. This devastating event paradoxically reshaped the town for the better: it generated a vast, flat shelf of new land below the main town. The Earl of Radnor later capitalised on this by building a highly lucrative toll road, which eventually evolved into what is known today as the Lower Leas Coastal Park.
Jump forward 242 years since that massive landlord and ask ourselves this: what has happened in those intervening years? Well, I can imagine we have since had 242 summers of various intensities and 242 wet autumns, winters and springs of various intensities. Those of us who are old enough can certainly remember the scorching summer of 1976. We can also remember the Great Storm of 1987 that devastated much of Kent.
We don't know what the cliff face and summit looked like before the great landslide of 1784, though I doubt it could have had trees on it. As I have said before, trees and then later coal were the main form of fuel to heat people's homes and cook with and to build with for centuries before oil, gas and electric and more recently nuclear energy were used to heat and light our homes and to cook with and run our industries.
About 5 years ago, I heard Canadian Professor Jordan Peterson, who was a guest speaker at the Cambridge Union on climate change and global warming. He made an amazing comment that there are far more trees in the Northern Hemisphere now than there were 100 years ago because people switched from burning wood and switched to coal.
I thought, blimey, he's absolutely right, as I remember as a 10-year-old back in the late 1960s when we had a coal fire in our council flat, there were about 200 such flats on our estate, which was bounded on one side by massive woods. My dad and I would chop up firewood from fallen trees and branches, as I'm sure others did, because even back then, coal was expensive, but you needed wood to get the coal to start burning.
By the time we moved away when I was 16 in 1974, we had electric heaters and an electric immersion heater to heat the water.
So I'm guessing the reason we see so many photos of the Leas with hardly any trees is that people simply cut them down to use to light their fires and to build with. That, after the late 1960s, like us in South London, as we switched from coal fires to electric heaters and electric immersion water heaters, so did they down in Folkestone.
So I firmly believe that trees along the Leas have only started to grow in the last 50 years or so because they simply weren't needed for firewood anymore or to build with.
So what has serilously changed since 1784 is the rapid growth of invasive trees such as Holm Oaks and Sycamores together with Scots Pine introduced to the Coastal Park at sometime that has replaced the tall grassy looking cliff face in older Victorain photos that makes the terrain look like a grassy hillock in to what it now looks like a Riviere terrain with tall trees growing up the cliif face from the toe of the cliff to the very summit along the whole of the Leas escarpment. The trees hide the topography, the lie of the land, giving a false impression of it being a tall cliff face, whereas old photos suggest a look of a grassy hillside.
We know that we have constructed in the last 200 years or so footpaths up and down the cliff face, such as the now recently closed Cow Path used by farmers on the summit to take their cows down to the rich pastures in the lower Leas to graze on. We know the Zig Zag path was constructed in 1921, and paths on either side of the Leas Cliff Hall, as well as a service road, were built in 1927, which itself cut into the cliff face.
We know sets of steps were built by the Metropole Hotel and by the War Memorial down to the lower Leas and further west at Radnor Cliffs. The Road of Remembrance was built, though originally called Slope Road. We of course know of the 3 sets of lifts built by the Victorians at the Radnor Cliff end going down to Sandgate, and the lift in front of the two hotels, and the only remaining lift on the Leas at the eastern end of the escarpment.
Now, to come back to the headline of this blog post, Has The Folkestone Leas Lift Company Created The Perfect Conditions For Another Landslide To Come?
Well, I am sorry to say, but I think yes, what they are doing at the toe of the cliff face seriously undermines the future stability of the Leas in that area. The land has settled there over the past 242 years, and now they have cut away a huge wedge of the cliff face, weakening the cliff's stability. Did they really need to do that? Could they not have simply built something across the road to satisfy their need to expand the project's footprint? De-Haan owns plenty of land there; he could have let them have some of it if the trustees had asked, I am sure he would have allowed them some land to build on. This would have saved them an awful amount of time and money, and the weakening of the cliff face, which is now happening, and will be a serious risk for a very long time to come. I don't blame the construction company doing the work; they are only doing what the Leas Lift Company Board of Trustees and their architect tasked them to build.
Was there really a need to disturb the cliff face further by excavating out such a large wedge of land from the toe of the cliff face just to extend the footprint and build another building, when they could quite easily have built something across the road and not spent all that absurd amount of money trying to shore up the cliff face?
They are certainly facing issues that have so far delayed the lift's opening by several months. I believe they had hoped to open in May, but now I doubt they will open before August, perhaps even later. They have had to double up on sheeting, mesh, and soil nailing as the uncompromising cliff face is ballooning out as the water-porous terrain, its ground structure, and topography is not giving up without a fight. I've said all along that soil nailing and mesh is a cheap form of trying to hold up any cliff face/hillside, and that they should have built a motorway-type retaining wall out of Gabion wire baskets tiered up the hillside, filled with rocks that help with drainage, or a concrete structure to retain the cliff face or to put in a steel sheet piling structure.
If they had carried out some investigations, then they might have unearthed the same information I have found quite by chance online and by simply sticking my head over the railings 100ft away from the Leas Lift in front of Cherition Place. I discovered that a serious landslide occurred at what I believe to be in front of Cheriton Place by the twin towers back around 2003. The photo I found and the information I got back from the company I located, which carried out the soil nailing and meshing at the time points to this exact location. Glancing over the railings a few months ago confirmed my thoughts when I could clearly see below and in amongst the dense vegetation was steel mesh/netting across a long stretch of the Leas and disappearing down the slope out of sight.
I believe the photo above shows a landslide that occurred around 2003; you can see men attending to the meshing and nailing of the cliff face. I believe the Leas Lift is just a few yards to the right of this photo. You can clearly see the sloping path at the bottom.
I have no idea why the Victorians did not use pile driving to construct a solid foundation on which to build a structural retaining wall at this site. They may well have done so when constructing the actual track, as that might well account for what is holding the huge heavy water tanks in place. They are quite literally wedged in by the sloping track.
Pile driving to "hit rock bottom" transfers a building's weight directly to solid bedrock when upper soil layers are too weak to support it.
The Victorians did use Timber Piles: Sawn logs, often treated with early wood preservation techniques to prevent rot, remained the most common material for foundation support.
They also used Iron Sheet Piles: Victorians pioneered the use of cast iron and early rolled iron "sheet piles" driven into riverbeds to form interlocking, watertight perimeters called cofferdams. This allowed them to pump water out and build massive stone bridge piers on dry riverbeds.
Concrete Piles: Toward the very end of the Victorian era (the late 1890s), early forms of reinforced concrete piles began to emerge, paving the way for modern construction.
I know three people who live in the Lees apartments, directly opposite the Leas Lift, and one individual who has raised his concerns with the company directly about the threat of any future landslide now that this wedge of ground has been cut out of the cliff face/hillside. His fears are justified. Soil nailing and meshing have repeatedly proven ineffective for retaining a cliff face or hillside prone to landslides when the material is weakened, such as sand/ poorly cemented sandstone, and Gault Clay, as we have here in Folkestone.
I have friends who live in those flats called the Lees Apartments who are considerably alarmed and concerned at the excavation at the toe of the cliff face directly below their properties, which could directly affect their homes should a landslide occur in this area now.
There are plenty of examples around the World where this system has failed quite dramatically, as the soil nails fail to take hold and are simply eased out by water pressure, internal ground movement, and weathering. Trapped pore water pressure pushes the soil outwards, exceeding the capacity of the mesh. There are several other reasons for soil nail and mesh netting failures, but already at this Leas Lift site, they had to double up their efforts by putting in even more blanketing and steel meshing and more soil nails, as what was there developed a ballooning outwards caused by the buildup of water pressure from behind. I have serious fears that once the building goes up at the bottom, perhaps one day in the future, given the right set of circumstances, like the perfect storm, a landslide will occur here.
Leas Lift Restoration Folkestone Part 1 YouTube video 20th March 2026
What you won't see on the Leas Lift Facebook page is any reference or photos or videos of them dealing with having to undertake an overlap and doubling up of more mesh netting and soil nails, as a ballooning outwards caused by the build up of water pressure, and what looks like a possible landslip above and to the right of the video shot.
Leas Lift Restoration Folkestone Part 2 YouTube video 20th March 2026
If you look closely, this is something you won't see in photos or videos on the Leas Lift Facebook page. Above, where they are working in the videos above and the photos below this, you will see rows of wooden pegs. You can also see what looks to me as evidence of a landslip/fissure in the photo I took on the 1st of June 2026, just by the tree line that runs across the site in a semi-arc.
A fissure in a cliff face is a fracture, crack, or natural gash along which a distinct separation occurs. These features are common in geological formations like chalk, sandstone, and limestone and are typically driven by erosion, weathering, and structural faults.
Key Characteristics
- Formation: Created by tectonic forces, pressure from freezing water, wave impact at the base, or gradual slope failure.
- Safety Hazard: Large fissures signal cliff disintegration and are the primary warning signs for imminent rockfalls or landslides.
- Management: In unstable coastal areas, such as the UK's Seven Sisters or Beachy Head, public authorities continually monitor these cracks. In more stable, inland rock faces, engineers may fill the fissures with specialised mortar to prevent water damage.
Below, you can see where the new mesh overlaid the original mesh with much wider plates than were originally used, affixing the soil nails into the hillside.
I believe these wooden pegs are commonly referred to as survey pegs or stakes and serve as a practical, low-cost method for tracking lateral earth movement on landslide-prone hillsides.
Why are they used on hillsides?
- Surface Monitoring: They are driven into the ground in a grid pattern. By measuring the spatial changes of these pegs over time, engineers can identify creeping soil or slow-moving landslides.
- Cost-Effective: They provide a simple, visual, and highly affordable way to monitor large, accessible slopes.
As I have said before, I don't lay any blame at the door of the construction company, as they are only carrying out the scope of the works as tasked by their employers, in this instance, the Leas Lift Board of Trustees and the architects who, it would seem to me, failed to grasp from the outset the enormity of what excavating a volatile site like this and the problems it would bound to entail.
I don't think we are being told the truth, and so far, to me at any rate, it looks like the issues they are having here at the toe of the cliff face are holding up the opening of the lift by perhaps many more months to come. There may well be major changes to come, like having to build a major retaining wall before they can construct the building they want to place in there.
I believe that the same level of threat of a landslide will always be hanging over us at the Vinery/Coastal Park play area, where they have used far shorter soil nails, half the length in fact, than they have at the Leas Lift. I also believe that Kent County Council is going to make the same fundamental mistake and create a similar threat and risk at the Road of Remembrance.
The photo below I took on the 1st of June 2026, I can't believe the extent of this vast area with its width, drop and sheer verticality of a site that almost certainly consists of shallow soil and fine sands and loosely cemented sandstone sitting on a bed of imporous gault clay at the toe of the hillside/cliff face.
Soil nailing is just as likely to weaken this site even more than the hope of strengthening it. Mother Nature is unforgiving. If these soil nails are not anchored well at the top, then any ballooning could force the whole lot to slide down the hillside with tons of soil and sand falling to the road below. If this takes 40 weeks, as they suggest, and they only started a few weeks ago, then they will be facing autumn and winter weather with plenty of rainfall and not much vegetation holding it all up, as they have virtually cut it all away to make way for the mesh and soil nails. One good downpour could put an immediate end to this project.
At the Vinery/Play area, they may well have used wider plates to hold the soil nails against the mesh, but these soil nails are half the length of those used at the Leas Lift site. This is because debt-ridden FHDC are paying for this and not at the lift site, lottery funding or at the Road of Remembrance site, the County Council taxpayers.
Corrosion: In coastal environments (such as near the cliffs in Folkestone), salt spray and moisture accelerate the corrosion of uninsulated steel nails and metal mesh, causing them to rust and lose their tensile strength over time.
Only Time Will Tell If They Have Gotten This Right.
Stephen West
Find us on Facebook Protect & Preserve The Folkestone Leas
Comments
Post a Comment