Snowdonia

The vital moment comes a couple of hours into the walk. I drop down from a tussocky hill towards the village of Y Fron. There’s an abandoned slate-quarrying machine and a grassy track that suddenly emerges on the rim of a deep lake-filled crater. The water is the colour of an old bruise. Around the rim is a fence of lichen-crusty slates like gravestones. It’s a dark, brooding spectacle and totally unexpected. At that moment, I know that whoever designed this route knew what they were doing.

This is the Llwybr Llechi Eryri (Snowdonia Slate Trail), an 83-mile hike that follows a great loop around the national park, starting in Bangor and ending in Bethesda. It strings together a series of abandoned slate quarries with some of the finest riverside and mountain walking in the UK. I’m doing just three days, starting in Llanberis and heading to Betws-y-Coed via stops in Beddgelert and Llan Ffestiniog.

Beyond Y Fron village, I descend into my first quarry, and it proves to be a classic. This was once the Dorothea slate quarry, a vast abandoned complex of railways, cottages and chasms. I start exploring: tunnels, cuttings, huge looming stone towers like Maya temples, all overgrown with ash, birch and oak. What strikes me is the craftsmanship and precision in construction, each stone hand-fitted without mortar, all for workaday industrial buildings.

The quality of this slate was known from early times. Edward I is thought to have had his Welsh castles roofed with it, but industrial production began in the 1820s and peaked in the 1870s. Soon, there was a railway to Caernarfon and the area bristled with steam pumps, aerial cables and chains. The last-ever Cornish beam engine was installed to pump water from the deep pits, sucking up 10 gallons a second from 500ft down.

From here, the trail burrows eastwards into the Welsh mountains, until Yr Wyddfa (Snowdon) appears on the horizon when it turns south, occasionally following the line of the Welsh Highland Railway all the way into Beddgelert, my first overnight stop. Named after a dog or a saint, depending on who you believe, this is a good base for hikers, having pubs, cafes, restaurants and outdoor gear shops.

The second day begins along a path combining the Slate Trail and the Cambrian Way, one of the grandees of the long-distance genre at 298 miles. I follow the route as it heads south along the River Glaslyn, with some spectacular sections on crags with the torrent below. We are getting along very nicely – so well, in fact, that I start to get footpath envy. When the Cambrian Way turns east, heading up the Matterhorn-shaped peak of Cnicht, I cannot resist. The weather forecast is bad, but the sun is out. If I pop over the peak, I can see how the two paths cross each other later.

Views of the Irish Sea open up as I climb, but there is an ominous black cloud approaching. As I reach the summit, a howling wind threatens to blow me off course. I face down the hailstones and get back to the Slate Trail, which now descends into Cwmorthin quarry. Not on the scale of Dorothea, Cwmorthin still seems epic today, dominated by vast heaps of spoiled stone – it took 10 tons to make 1 ton of marketable material. In the late 19th century, Cwmorthin was known locally as “the slaughterhouse” for its propensity to slay workers in fatal accidents. From here, the path runs down a desolate valley before dropping into Blaenau Ffestiniog, where I find a good cafe, Burrito Blasus, to fire me up the last miles into Llan Ffestiniog.

I stay in the Y Pengwern, a community-owned pub that has an excellent, friendly bar and basic rooms and food. Outside, a storm is buffeting the building, but the next day the rain has stopped and I begin with a rare treat: a magical trail beside the tumbling River Cynfal. Here, thunderous white spumes of water and dark powerful currents punch their way through a deep mossy gorge overhung by ancient fern-decked oaks. One of the midstream rock towers is said to have once been the “pulpit” of a magician called Huw Llwyd and, according to the 18th-century traveller and naturalist Thomas Pennant, his voice could be heard at night, ringing down the enchanted chasms.

As I climb higher, the forest dwindles and I emerge on a remote, wind-scoured upland of crags and bog. Even here, you can come across fragments of old quarry workings. In one abandoned cottage, a jacket still hangs on a nail behind the door, as if the occupant had just flounced out: “I’ve had enough. I’m off to America.” Many Welsh slate workers did head to the US, fed up with the poor pay and the repeated failure of strikes. In 1901, sympathetic workers in England sent a two-and-a-half ton Christmas pudding, which briefly lifted morale, but after violent clashes the landowner won, and many quarrymen emigrated.

I stop and brew some tea on my stove. I have not seen another soul all day, yet Yr Wyddfa, with all its crowds, is less than 10 miles away. This remote walk takes me to the top of the old tramway incline down to Rhiwbach quarry – an epic approach, descending to the old engine house. This place peaked in the 1860s, and being so isolated, the miners lived in barracks, some of which remain.

Farther down the valley, I spot peregrine falcons nesting close to a tumbling waterfall, above the little village of Cwm Penmachno. A few miles on, the church of St Tudclud contains an astonishing collection of inscribed stones, including the Carausius Stone. This is thought to be the gravestone of a commander of the Roman empire, who pulled off a coup d’etat in AD286, making himself emperor of Britain and northern Gaul for seven years before his assassination.

Approaching Betws-y-Coed, the path joins the River Conwy, first singled out as a beauty spot in the 17th century, long before the Romantic poets seized on the idea. For me, it’s the finale to this fine route, but the path continues and I’ll be back soon for more mountains of slate and spectacular riverside walking.

The trip was provided by Walkers’ Britain & Europe, which offers Hiking the Snowdonia Slate Trail as a seven-day self-guided 83-mile walk, including six nights’ accommodation, breakfast, luggage transfers, digital app with tour information and navigations, and emergency hotline from £890pp, departing daily from April to October