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At the summit of Honister Pass, at 1,167 feet above sea level in the heart of the western Lake District, there is a working slate mine. Not a heritage attraction. Not a museum. A working mine — one that has been producing green Westmorland slate since the 17th century and is still producing it today.
It is the last working slate mine in England.
This fact alone is worth sitting with for a moment. Slate mining was once one of the primary industries of the Lake District — hundreds of quarries and mines operated across the fells, extracting the distinctive green and blue-grey stone that covers the roofs of almost every traditional building in the region. One by one they closed, as cheaper imported slate undercut the local product and as the most accessible seams were worked out. Honister is the last one standing.
The slate at Honister is not what geologists technically call slate — it is actually a volcanic rock called rhyolite tuff, formed from compressed volcanic ash during the Ordovician period approximately 450 million years ago. Over millions of years of heat and pressure, this volcanic material was metamorphosed into the hard, fine-grained rock that splits cleanly along natural planes — the property that makes it useful as a roofing material.
The Honister tuff has a distinctive green-grey colour caused by the mineral chlorite, which gives it the characteristic appearance of traditional Lakeland roofing slate. It is harder and more weather-resistant than many other slates, which is why buildings roofed in Honister slate are still sound after two or three centuries.
The seam runs through the summit of Honister Pass at a steep angle — which is why the mine is at the top of the pass rather than lower in the valley. The miners follow the seam into the mountain horizontally and at depth, extracting the rock by hand and machine. The distinctive green spoil heaps visible on the hillside above the mine are the waste material from centuries of extraction — the off-cuts and rubble from splitting the rock into usable tiles.
The mine has been worked since at least the 17th century, when records first mention slate being extracted from the Honister seam. For most of its history it was a hand operation — miners working by candlelight deep in the mountain, splitting rock by hand with hammer and chisel, and dragging the raw slate to the surface on wooden sledges or in baskets.
The Victorian period brought mechanisation — tramways were built up the steep fellside above the mine to carry slate from the highest workings down to the processing buildings at the mine entrance. The inclines are still visible today, their steep lines cutting up the hillside at angles that seem almost impossibly steep. Horses worked some sections; gravity did most of the work on the descent.
By the mid-20th century the mine was struggling. Cheaper imported Welsh and Spanish slate had captured most of the market and the Honister operation was barely viable. It closed in 1986.
In 1997 it was bought and reopened by Mark Weir, a local entrepreneur who saw the potential of combining a working mine with a heritage attraction. Under his ownership Honister became profitable again — the combination of continuing slate production with guided mine tours, a via ferrata route on the crags above and a successful retail and online business selling Honister slate products made it viable in a way that pure production could never again be.
Mark Weir died in a helicopter crash on the summit of the pass in 2011 — a loss that devastated the local community. The mine continues to operate under his family.
We make a ten-minute photo stop at the mine entrance on our The 10 Lakes Full-day Tour with Ullswater Cruise. We do not go inside the mine on this tour — the interior tours take longer than our schedule allows — but the exterior of the mine at the summit of Honister Pass is dramatic and entirely worth stopping for.
From the road you can see:
The Victorian tramway inclines — the steep lines cut into the fellside above the mine, along which slate was brought down from the higher workings. They run at angles of around 1-in-2 in places — steeper than most ski slopes.
The spoil heaps — the green-grey waste material from four centuries of extraction, spread across the hillside in great fans. They have a particular beauty — the colour of the rock against the brown and purple of the surrounding fell is distinctive and, once you know what it is, unmistakeable.
The mine buildings — the processing shed, the shop and the via ferrata departure point, clustered at the summit of the pass. They have the slightly improvised quality of a working industrial building that has grown over time rather than been designed — sheds added to sheds, equipment stored outside, the functional rather than the decorative.
The pass itself — Honister Pass is genuinely impressive. The road climbs steeply from Borrowdale to the south and drops steeply to Buttermere to the north. The valley walls press in close. The summit is narrow and windswept. Standing at the mine entrance with the fells rising immediately above and the Borrowdale valley falling away below, you have a clear sense of how high and how remote this place is.
For those interested in returning independently, the Honister mine offers a via ferrata — a fixed-rope mountain route up the crags directly above the mine. It is one of the few via ferrata routes in England and gives access to the summit of Grey Knotts at 697 metres. Booking is essential — check honister.com for current availability.
The road over Honister Pass connects Borrowdale to the south with Buttermere to the north. It is the highest and steepest pass in the western Lake District, with gradients of up to 1-in-4 on both sides.
The southern approach from Borrowdale climbs through the Jaws of Borrowdale — the dramatic gorge where the valley narrows to almost nothing — past Seatoller and up to the summit. This is the approach we take on the Ten Lakes Tour, driving south through Borrowdale and climbing to the mine.
The northern descent to Buttermere is equally dramatic — the road drops steeply with the great cirque of High Crag, High Stile and Red Pike rising ahead of you, and Buttermere appearing in the valley below as you descend.
Can I visit Honister Slate Mine independently?
Yes — Honister mine is open to visitors most days throughout the year. They offer guided mine tours, a via ferrata route, a shop selling Honister slate products and a café. Check honister.com for current opening times, tour times and via ferrata booking.
Is Honister really the last working slate mine in England?
Yes. There are still slate quarries in Wales and elsewhere in Britain, but Honister is the last underground working slate mine in England. The distinction between a quarry (open-cast extraction) and a mine (underground extraction following a seam) matters here — Honister is a mine, not a quarry.
What is Westmorland slate?
Westmorland slate is the green-grey volcanic rock extracted from the Honister seam and from several other locations in the former county of Westmorland (now part of Cumbria). It is the roofing material used on the vast majority of traditional Lake District buildings — farmhouses, barns, field walls and estate buildings throughout the region. Its green-grey colour is one of the defining visual characteristics of the Lakeland landscape.
How steep is Honister Pass?
The steepest sections on both the Borrowdale and Buttermere approaches reach approximately 1-in-4. Both sides are narrow and require care when passing oncoming traffic. In winter the pass can close due to ice or snow — check conditions before driving.
Is Honister Pass suitable for larger vehicles?
The pass is challenging for larger vehicles, particularly campervans and coaches. Our licensed minibuses are well suited to it. If driving independently in a larger vehicle, check the road width before attempting it.
Honister Slate Mine and Honister Pass are on our The 10 Lakes Full-day Tour with Ullswater Cruise. Check availability and book here.