The most dramatic volcanoes in Britain: discover 7 mountains with explosive pasts

It has been around 60 million years since there was an active volcano in the UK, but remnants of these explosive landforms can be found throughout the countryside...

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Published: November 13, 2023 at 8:13 am

Britain may not be in the Ring of Fire, but things were quite different around 60 million years ago. Today, remnants of huge volcanoes dot the landscape. You may be surprised to find that you've already hiked up some of them.

Read on to discover seven of Britain's most incredible extinct volcanoes, from Snowdon and Ben Nevis to the Isle of Skye's Black Cuillin.

Climbing a winter mountain
Hikers make their way to the summit of Snowdon, once an active volcano/Credit: Getty

What is a volcano?

A volcano is created when there is a rupture in the surface of the planet, which causes volcanic ash, hot lava, volcanic ash, and natural gases to escape from the opening in the magma chamber and through the Earth's crust. This crust is made up of rigid tectonic plates that lay on top of a hotter, softer layer in the mantle.

Many of the UK's mountainous areas, such as the Lake District were formed through volcanic activity more than 300 million years ago. When magma reaches the surface of the Earth it is called lava, which when it cools forms rock.


7 extinct volcanoes of the British Isles

Cuillin Hills, Isle of Skye

Cuillin Hills, Isle of Skye
The highest mountain in the Cuillin Range is Sgurr Alasdair 992 m/Credit: Getty

The Cuillin Hills on Skye are considered by many to be the most dramatic mountains in the UK. If they look fearsome now, imagine what they must have been like at the height of their lava-spewing life in the early Paleogene era, around 65 million years ago. The Black Cuillin Mountain itself is a particularly awe-inducing sight, making it the most impressive former volcano on these islands.

Experience the Cuillin Range from the air/Credit: The Great Outdoors

Snowdon, Wales

Mountain range in winter with frozen lake
One of Snowdonia's eruptions was thought to heard 3,000 miles away/Credit: Getty

Snowdon mountain in Wales was once at the centre of a furious ring of volcanic activity. One such eruption in the region is believed to have been about three times as explosive as the Krakatoa in Indonesia. That eruption was heard 3,000 miles away and altered global climates and weather for years afterwards. So perhaps before it happened Wales was bathed in sunshine all year round...


Ben Nevis, Scotland

Ben Nevis in snow
Ben Nevis – the highest volcano in the UK/Getty

Scotland's highest mountain was also once a large and active volcano. During one extreme eruption in the Carboniferous period it caved in and destroyed itself. All that remained is the collapsed inner dome of the volcano, which we know now as Ben Nevis. Scientists believe the explosion would have been in the same league as Snowdon's eruption.


Borrowdale Hills, Lake District, England

Borrowdale hills
The once-volcanic Borrowdale hills sit in the middle of the Lake District National Park/Cedit: Getty

The Borrowdale hills in the Lake District are of a similar age to those in Snowdonia and were once just as explosive. Another British super-volcano, they have reached the grand age of 450 million years and, despite creating some of England's most stunning landscapes, have long since retired.


Ardnamurchan Peninsula, Scotland

Ardnamurchan Peninsula, Highland
Sunrise overlooking Loch Shiel from the breathtaking Ardnamurchan Peninsula/Credit: Getty

The Ardnamurchan Peninsula and the Isle of Mull on the west coast of Scotland are remnants of volcanic activity that ended around 55 million years ago but which would have rivalled Iceland's eruptions in their heyday. It might not be immediately obvious on the ground, but looking from the air the concentric rings of the points where lava spluttered up to the surface.

Arthur's Seat, Scotland

Arthur's Seat, Edinburgh
Arthur's Seat overlooks the city of Edinburgh/Credit: Getty

The enchanting Scottish capital is home to not one, but two extinct volcanoes. The inventively named Castle Rock, on top of which is perched Edinburgh Castle, is one of them. Arthur’s Seat, the highest point in the city, is the other. Both have been inactive for about 350 million years, so residents of the vibrant city are likely to be safe.

Glen Coe, Scotland

Glen Coe Scotland
Explore the majesty of Glen Coe/Credit: Getty

Glen Coe is all that is left of an ancient super-volcano, erupting about 420 million years ago. It's considered a classic example of cauldron subsidence. This awe-inspiring part of the Scottish countryside contains the spectacular pyramidal Buachaille Etive Mòr mountain and a steady stream of keen hikers.

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