On a clear summer’s day, the view looking west from the Rhins of Galloway peninsula is a beautiful one.
You see the green and rocks of the Scottish foreshore, the wide sunlit blue of the Irish Sea and, on the horizon, the craggy outline of Northern Ireland some 20 miles away. It’s a scene to calm the mind. But, hidden from view, there’s a story under the waves.
On the seabed here, running roughly northwest to southeast, stretches an enormous underwater trench. It was formed by glacial activity in the dim and distant past and measures around 30 miles in length, two miles in width and up to 300 metres in depth.
Today it goes by the name Beaufort’s Dyke. Ordinarily, a sea trench of this size would chiefly be seen as a natural wonder, but Beaufort’s Dyke – one of the very deepest points in British waters – has a rather different claim to fame.
- Famous shipwrecks: Discover dramatic stories of eight lost ships beneath our seas
- Prison ships, German submarines and shallow graves: the terrible tale of Britain's own Dead Man's Island
Beginning in the early 20th century, and most notably in the aftermath of the Second World War, the trench was used as an offshore dump site for stockpiles of unused bombs, shells and chemical weapons.
The Ministry of Defence has estimated that it holds in excess of a million tons’ worth of unexploded munitions, including bombs surrendered by German forces.
Short dumping
The trench – located close to the site of the key Second World War port, Cairnryan Military Harbour, from where much of the dumping took place – was seen as a conveniently massive receptacle for disposing of dangerous materials at a depth that would minimise the impact of any unforeseen explosions.
Among the munitions left in the dyke were around 14,500 tons of 130mm artillery rockets filled with the toxic gas phosgene. It’s also been reported that two tons of concrete-sealed radioactive waste were deposited in the 1950s. Things must be pretty cluttered down there.
- Wimbledon as a pig farm? Wembley an evacuation centre? 11 iconic sports venues that transformed during the Second World War
- Unsolved mysteries, German battleships and Henry VIII’s favourite war vessel: Discover 10 shipwreck sites in the UK
“It was identified originally as a relatively safe and low-risk disposal area,” explains Keith Higgins, an unexploded ordnance (UXO) consultant at specialist company Ordtek. “A lot of the munitions dumped in the area were defused, but the reality – and what makes things troublesome – is that there was also a lot that was dumped that was non-compliant.”
This means not only that some bombs were deposited with their fuses still intact, but that not everything intended for the trench made it to its designated resting place. There’s evidence that when crews carrying the munitions were pressed for time or hit bad weather, they engaged in “short-dumping”. This involved dropping the waste in shallower waters, in some cases just hundred of metres from the shoreline in Galloway.
It’s the likely explanation as to why, shortly after work began on laying an undersea pipeline close to the dyke in the mid-1990s, thousands of incendiary devices were washed ashore. They contained phosphorus, cellulose and benzene. A four-year-old on the Mull of Kintyre received burns after picking one up and bomb disposal teams were hurriedly dispatched to remedy the situation.
Marine risk
There are also environmental considerations. Studies have generally found no widespread contamination of the surrounding seabed or marine life, and leakage from chemical munitions is likely to be localised rather than extensive.
Yet the greater practical concern is disturbance – whether by fishing, anchoring or seabed construction. Similarly, the dangers from terrorism cannot be overlooked. The main issue, however, remains the unknown but significant quantities of munitions that were short-dumped. When ex-Prime Minister Boris Johnson championed the idea of a road bridge between Galloway and County Antrim in Northern Ireland,
the risks posed by these weapons were an obvious hurdle. The whole area also exists under a shipping lane, ferry routes and fishing grounds.
What can be done?
“The answer to that, unfortunately, is another question,” continues Keith. “What’s in the interest of public safety and clearing up the seabed, versus taxpayer cost? That’s the reality. We’d all like to see the munitions removed, but even just based on the water depth, let alone the breadth of contamination, the cost of mitigation means it’s probably never going to be solved. It’s one of those legacies of war.”
The dyke itself takes its name from Sir Francis Beaufort, the Irish hydrographer who developed the Beaufort Scale in 1805, a system still widely used for measuring high wind speeds at sea. Are there stormy waters ahead for this enormous trench and its contents? Only time will tell.
Main image: Located half a mile from Portpatrick on the west coast of Scotland, 12th-century Dunskey Castle sits on cliff edge that overlooks the deepest section of Beaufort's Dyke. (Photo: Getty)
