One of the best-kept secrets of the war, the story of 200 men who prepared the way for the Allied invasion of the European continent was disclosed in August 1945 in a Reuter message. Six weeks before D-Day a surgeon-commander, one of Britain's leading physiologists, was sent for by the Admiralty. They told him that as well as laying mines along the French coast the Germans had constructed elaborate submarine obstacles.
“You have six weeks before D-Day”, he was told. “Before then you must find out what the human body can stand in the way of submarine blast, devise a blast-proof diving suit, and train men. Mines must be cleared and obstacles blown up.”
The Commander began immediate experiments with volunteer “guinea-pigs”, himself among them, and discovered the very important fact that an air bubble offered resistance to blast. Working day and night he devised a diving suit of sponge rubber and kapok capable of withstanding several hundred pounds pressure per square inch. Meanwhile concentrated training was going on of the 200 men specially selected from hundreds of volunteers for this most dangerous job. The strictest secrecy was of necessity observed.
It was necessary to carry out the vital demolition work as near to D-Day as possible. A few nights before D-Day a little fleet crept across the Channel in the darkness, stopping a few hundred yards from the Normandy coast. No sign came from the coast that the fleet had been observed, and 200 divers in their special suits, carrying apparatus for laying demolition charges slipped quietly into the sea.
Demolition machinery is usually operated from aboard ship, but for the destruction of the submarine obstacles it was essential that the divers should be very near the scene of the explosion to avoid the danger of long wires braking. The men aboard ship waited anxiously for hours. Eventually there was a series of muffled explosions. The divers' work was done.
They clambered aboard the ships and started for home under a volley of machine-gun and rifle fire from the Germans, who, aroused at last, began firing wildly in the direction of the noise. But they were too late; the gateway to the Continent was opened, and owing to the efficiency of the diving suits not one diver was lost.