Swanage pier

Becky Hitchin continues her geological tour of Britain’s coastline. Part 3: The nation’s south and west.

So now we come to the part of UK diving that most people reading this article know better than me. But I’ll do my best. 

Dorset. Swanage. Now I have to admit that the only time I’ve ever been to Swanage was when I was about 12, on a family holiday. All I can remember was a shop with really good apple doughnuts, and lugging the family’s dinghy to the beach. So, this may be a slightly biased account of one of the most famous shore dives in the UK. If I took my knowledge of Swanage Pier from the pictures I’m always amazed at in my Facebook account, I would think that: (a) Tompot blennies have a collective modelling agency that farms out particularly photogenic examples to each photographer as they enter the water. And (b) the water sometimes seems to be some really strange shades of pink, yellow and orange. Of course, that might relate to the skill of all the photographers down there and their access to shiny new lens systems, and particular photographers liking filters on their shiny lens systems, but I choose to believe the former, and will expect exactly that when I finally manage to dive Swanage. 

Devon and Cornwall form the south-west tip of the UK and are lands of two halves

Devon and Cornwall - you’ll be pleased to know I have actually managed to dive in each of these counties. Devon, unsurprisingly I know best from the late lamented Fort Bovisand where I first realised how loudly dive instructors tend to snore, amplified by the echoing, arched roof dormitories.  

But let’s get back to geology. Devon and Cornwall form the south-west tip of the UK and are lands of two halves. Their north coasts are wilder and more exposed compared to the more sheltered southern coasts of clotted cream teas, wide estuaries and sheltered anchorages. The Scilly archipelago, off the south-west tip of England, encompasses both of these with shallow sandy sediments colonised by extensive eelgrass beds and reefs exposed to the full force of the Atlantic. 


On towards Wales, via the wide Severn estuary. First – before we cross the border, we would have once encountered the late, lamented NDAC (National Diving and Activities Centre, now the domain of secret projects). Geology is pivotal for our quarry diving, as well as diving in the sea. NDAC was formed from a former limestone quarry which produced around 60 years of crushed rock for construction and agriculture, its depths and steep sides a result of that intensive activity. Quarries created from gravel dredging or chalk pits, by the way, tend to be shallower, with more sloping sides. A wander in from the shore rather than a jump off a floating platform because the rock being taken out just isn’t as strong as limestones or volcanic rocks. 

In Wales, I want to take you to a dive under a bridge. I wish I could say that I had a good experience of diving in the Menai Strait, but the last time I dived there, my buddy insisted on dragging me away from interesting sponges to show me pieces of kelp for the entire dive. I can however confirm that the North Wales kelp is excellent, but what most people dive there for are the numerous, large yellow and orange sponges that dominate the strait. Why is this dive possible? As with many features we’ve seen, because of ice. Glaciers flowed down from Snowdonia exploiting underlying geological weakness and created a series of linear bedrock scours – the deepest of which became the Menai Strait. 

I wish I could say that visibility gets better as you head up the west coast of England. But it doesn’t. From Morecambe Bay all the way up to the Clyde is sand and mud, strong tides and a potential long walk out – or back - across mud flats. When we get to the Clyde, we reach the biggest river input since the Mersey. This is another inherently industrial area, full of naval yards and top secret submarines, and while most of the well-known dives are wrecks, the more adventurous dive operators are discovering scenic shore and boat dives aplenty in the lochs and islands of the area.

Article ‘As above, so below’ by Becky Hitchin first published in SCUBA magazine, Issue 134 April 2023.

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