Heligoland is a small island in the North Sea some 35 miles off the coast of Schleswig-Holstein, northwest of Hamburg. It is about a mile long and a half-mile wide, with steep red sandstone cliffs180ft high at the northern end. The neighbouring island of Dune is little more than a large sandbar. Known to some older people in England as a former shipping-forecast area (it became German Bight in 1956), Heligoland has a complicated history and for about a century was actually under British rule. These days it’s better known as a seal and seabird sanctuary and a duty-free resort.
In the Middle Ages, ownership of Helgoland (German spelling) fluctuated between Denmark and the Duchy of Schleswig, becoming incontestably Danish after 1714. A century later, at the height of the Napoleonic Wars, the British feared that neutral Denmark was going to enter an alliance with France, and the Royal Navy was sent to invade the island with a pre-emptive strike successfully achieved in 1807. Thus the island joined Gibraltar and Malta as a strategic landmark for the British military and a base for the Royal Navy.
In 1890, however, Britain agreed to cede the island to Kaiser Wilhelm’s Prussia in exchange for Germany’s agreement to give up its spurious claim to Zanzibar, an island that Britain coveted for commercial reasons and later annexed even though it was technically independent at the time.
The Germans soon developed their new possession with a dockyard and railway, and fortified it with massive gun emplacements and tunnels. Heligoland became an island fortress to protect the coast and the estuary of the River Elbe. It also sheltered minelayers and submarines, which the Germans put to good use during World War I when the islanders were evacuated and thousands of German troops occupied the island. After Germany’s defeat in WWI, the Treaty of Versailles required that all military installations on the island be dismantled.
The island was fortified again after Hitler came to power, but on a much larger scale. By 1941 hundreds of reinforced gun emplacements, bunkers and flak towers had been built, and a massive submarine pen 156 metres long and 94 metres wide contained five 250-ton U-boats. There were underground ammunition stores, and a vast network of service tunnels and command centres. Tunnels were also built as air-raid shelters for the civilian population.
The naval base and fortress island was considered a major threat by the Allies and became the target of mine-laying and bombing operations by the Allied air forces. The first RAF bombing raid in December 1939 was followed by a series of attacks throughout the war which left the island a mass of craters and wrecked buildings. The immensely strong U-boat pens, however, resisted until April 1945, when a massive raid by over nine hundred Halifax and Lancaster aircraft, some armed with Tallboy bombs, left the island uninhabitable. The war in Europe ended three weeks later.
After the war, Heligoland came under British military control as part of the Hamburg sector. In July 1946 a reconnaissance party was sent to report on what was left of the German occupation. They found huge quantities of German munitions, high explosives, depth-charges, shells and mines stacked in part-damaged underground bunkers and tunnels. It was decided that the only solution was to blow the whole lot up in one go, and over 400 tons of TNT and detonators were imported by the Royal Navy and packed in position over the next few months.
Thus on 18 April 1947 a small flotilla of British warships was stationed about ten miles to the south, small explosions were detonated to scare away migrating seabirds, the photographers steadied their tripods, and at precisely 1100 hours Operation Big Bang’s firing button on HMS Lasso was pressed. The explosion was enormous, and is regarded as the largest-ever in peacetime. Seismographs as far away as London and Paris recorded the event.
The island remained under British control for five more years, during which time it was used as a convenient target for RAF bombing practice. It was formally handed back to Germany in March 1952, giving the German authorities the awesome task of clearing the wreckage, defusing unexploded ordnance and making Heligoland habitable again. In the 1950s and 1960s new houses sprang up along paved alleyways, many with extra rooms to serve as tourist accommodation. The present population is about 1,100.
Just one shelter tunnel remains accessible, entered in the upper part of the town, via a double staircase some 15 metres deep. The air-raid shelter/tunnel runs slightly downhill and is bare save for a few electrical bits and modern lighting. There are a few side rooms, originally for meals/medical/toilet/mother-and-baby use. After 85 metres the tunnel was blocked; this was where the rest of the tunnel leading to a cliff entrance had been destroyed by the RAF.
A connecting tunnel turns almost at right angles to the first; this runs slightly uphill for a further 180m or so. Some side rooms have a few bits of old equipment but they may not have been original. Return to the surface takes place up a steep staircase into a little garden in another part of the upper town.
References:
- After the Battle, number 154 – Heligoland