WHAT’S THE STORY?

PRIME Minister Boris Johnson seems determined to at least investigate the possibility of building a “Union Bridge” between Northern Ireland and Scotland.

A major problem for Boris and all those who want to see a bridge built between Portpatrick and Larne is Beaufort’s Dyke, a massive natural formation at the bottom of the North Channel, where huge amounts of military waste were dumped – as much as 1.15 million tons after both world wars – as well as radioactive waste.

WHAT IS THE DYKE AND HOW BIG IS IT?

BEAUFORT’S Dyke – named after Sir Francis Beaufort, the naval hydrographer who devised the Beaufort Scale of wind measurement and discovered the dyke – is a huge deep sea trench that lies in the middle of the North Channel right in the area of the proposed bridge.

The dyke is about 31 miles (50km) long and up to 1000ft (300m) deep. At its widest it is approximately two miles (3.5km) wide with its nearest point to the Scottish coastline just six miles (10km) off the Mull of Galloway.

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That would make it an incredibly formidable obstacle in itself, but it is what is contained in the dyke that makes it potentially lethal and which will surely see the whole project abandoned if there is to be any disturbance of the sea bed.

WHAT IS DOWN THERE?

THAT’S what we don’t know for certain, but what has been established as fact is that Beaufort’s Dyke was used as a dumping ground by the British military for decades from the 1920s to the 1970s.

After both world wars, staggering amounts of munitions were taken from Cairnryan and dumped into the dyke – some of those munitions were thrown into the North Channel before the vessels carrying them even reached the dyke.

The Ministry of Defence has admitted that at least 1.15 million tons of military waste was put into the dyke, which was the largest offshore dumping ground the government used. The Ministry of Defence has always tried to conceal what was dumped in the Atlantic off Scotland but in 1995 the armed forces minister at the time, Nicholas Soames, was forced to tell parliament that the material dumped further out in the Atlantic included 17,000 tons of captured German bombs filled with the nerve gas tabun.

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The vast majority of the waste in Beaufort’s Dyke appears to have been redundant unused bombs and shells but 14,500 tonnes of 5-inch artillery rockets filled with phosgene gas were dumped there in July 1945.

In 1997, the government acknowledged that radioactive waste encased in steel drums had been dumped in the dyke in 1950s. The then secretary of state for Scotland, Donald Dewar, said the dumping had come to light through “a discovery of old papers in the Public Records Office”. He was at pains to assure MPs the waste was low level and no dangerous radioactivity had been discovered at the dyke.

In 1995, four-year-old Gordon Baillie of Campbeltown picked up a bomb washed from the dyke and was burned by the phosphorus it contained. A gas pipeline installed through the dyke loosened off thousands of such incendiaries which floated ashore on the west coast of Scotland.

DID YOU SAY INCENDIARIES, POISON GAS AND RADIOACTIVE WASTE?

YES, and this is where Boris Johnson might just have a big problem. International pressure is growing to clean up the seabed, and, as usual, the principle of the “polluter pays” is expected to be applied.

So if Johnson decides to go ahead with the bridge, the MoD and the Westminster Government could be hit with a multi-billion-pound bill to clean up the dyke and all the other areas where munitions and military waste were dumped.

Incidentally, the European Union has a directive telling each member state with a sea coast to tackle “marine litter” this year, which presumably involves the stuff dumped in Beaufort’s Dyke – could that have been another reason to “get Brexit done” by January 31?

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COULDN’T THERE JUST BE A FLOATING BRIDGE?

IT’S theoretically possible, but the technology is in its infancy. The world’s longest floating bridge in Seattle in the US is just 1.5 miles (2.4kms) long.

Nor has any such bridge been installed in seas as ferocious as the North Channel.

If the bridge gets the go-ahead, then the dyke will probably have to be cleared first.

Ministers should then remember what happened in 1967 when an attempt was made to raise the wrecked munitions ship SS Kielce from the seabed four miles off the Kent coast.

It exploded, causing an earthquake that measured 4.5 on the Richter scale and damaging properties in Folkestone.

That is the reason why government policy ever since has been to leave dumped waste undisturbed in the sea.