From his personal effects, the man was identified as Major William Martin, a temporary captain and acting major in the British Royal Marines. Rather than allowing possible military intelligence to go unintercepted, the local agents for the Abwehr-- the German intelligence organization-- coaxed the briefcase open to examine its contents. Inside, along with the man's personal effects, the Nazis discovered a personal correspondence between Lt. Gen. Sir Archibald Nye, vice chief of the Imperial General Staff, and General Sir Harold Alexander, the British commander in North Africa. This letter described key details of the Allies' plans to invade Nazi-held territory. It seemed that luck was favoring Germany; but the discovery ultimately resulted in disaster for the Nazis.
Within days, the body was turned over to the British military, and he was buried with full military honors in Huelva. But the British Admiralty demanded the return of the documents, emphasizing discretion due to their sensitive nature. The government of Spain was compelled to respond because the country was technically a neutral party in the war, although they were sympathetic to the Nazi cause. The documents were indeed returned to the British military thirteen days later, but not before the German Abwehr agents teased open the sealed letters, photographed the entire contents of the briefcase, and resealed the envelopes to alleviate suspicion that the letter's contents had been discovered. The photographic evidence was then rushed to Berlin, where the images were carefully analyzed.
Wary of a ruse, German intelligence examined the officer's personal effects in great detail. His possessions included numerous benign items such as a photograph and love letters from his fiancée, a set of keys, recently used ticket stubs for a theater performance, a hotel bill, etc. A close inspection and investigation strongly suggested that these items were genuine, indicating that Major William Martin and the documents on his person were authentic. A second letter in the dead man's possession-- this one from the Chief of Combined Operations to the Commander-in-Chief in the Mediterranean-- contained text indicating that Major Martin was carrying a letter too sensitive to be sent through normal channels, hence the need for him to fly.
By all appearances, the Axis powers had stumbled upon extremely valuable intelligence, unbeknownst to the Allies; a letter which indicated exactly which beaches the Axis powers would need to reinforce in order to repel the Allied invaders. The document discussed key details of "Operation Husky," a secret Allied plan to invade Nazi Europe by way of Sardinia, Corsica, and Greece. It also described a plan to prepare a false attack upon Sicily-- the location where Germany expected the Allies to attack-- as a way of drawing German forces away from the true invasion site.
Upon learning of the letter, Adolph Hitler took decisive action based on the information it disclosed. On May 12, he sent out an order: "Measures regarding Sardinia and the Peloponnese take precedence over everything else." He diverted significant defenses away from Sicily to the indicated points of hostile ingress, including an extra Waffen SS brigade, several Panzer divisions, patrol boats, minesweepers, and minelayers. But when the day of the attack came, all was relatively quiet on the beaches of Sardinia, Corsica, and Greece. The Germans had fallen for an elaborate deception designed to draw Nazi defenses away from the true Allied target: Sicily. Major Martin-- the dead man the fisherman found on the beach-- never existed.
The idea to plant false military documents on a dead man and let them fall into the hands of the Germans was conceived by Lt. Cmdr. Ewen Montagu at British naval intelligence. His was a variation of an earlier idea proposed by Flight Lt. Charles Cholmondeley of the counter-intelligence service MI5. Cholmondeley had suggested that a wireless radio could be placed on a dead soldier whose parachute was rigged to appear to have failed, which would provide the Allies with a channel to provide disinformation to the enemy. But his plan was deemed impractical, so Montagu's death-at-sea ruse was implemented instead, and dubbed Operation Mincemeat.
Montagu's team quietly procured the body of a 34-year-old man who had recently died with pneumonia, whose lungs already contained fluid as a drowned man's would. The family of the deceased granted permission to use the body for this mission on the condition that the man's identity never be revealed. As the body waited in cold storage, the fictional life of Major William Martin was fabricated in great detail by the Twenty Committee (often referred to by the roman numeral XX or "double-cross"). The corpse was given identification, keys, personal letters, and other possessions. In order to explain why the man would be found chained to his briefcase, Montagu's team planted evidence suggesting that Major Martin was an absent-minded but responsible chap, including overdue bills and a replacement ID card. Such a man might chain himself to a briefcase full of sensitive documents in order to prevent its loss during the flight.
On 28 April 1943, Major Martin was placed aboard the submarine HMS Seraph in a special steel canister packed with dry ice. The crew set off for the coast of Spain, where it was likely that a citizen of the Axis-aligned country would locate the body and report it to authorities. After two days at sea, the submarine surfaced about a mile off the coast of Spain at 4:30 in the morning. Believing that the heavy canister contained top secret meteorological equipment, members of the crew carried it on deck, after which point everyone aside from the officers was ordered below deck. There in the dark, Lt. Norman L.A. (Bill) Jewell, the commander of Seraph, explained the mission and swore the men to secrecy. Major Martin's body was then removed from the canister onto the deck, where he was fitted with his life jacket and chained to his briefcase. The men read the 39th Psalm and committed the body to the sea, where the tide gradually drew it ashore.
Once the body was discovered, Britain's requests for the return of the briefcase helped complete the illusion that there was sensitive information contained therein. To further the hoax, Montagu arranged to have Major Martin's name included on the next British casualty list in The Times. When the documents were finally returned to the British two weeks later, microscopic examination revealed that the Germans had indeed opened and resealed the letters. Additionally, German transmissions decrypted by Ultra indicated that the Nazis were moving forces to defend Sardinia, Corsica, and Greece. This news prompted a brief cable to Winston Churchill to inform him of the success: "Mincemeat Swallowed Whole."
On 09 July 1943, Allied forces launched the real Operation Husky, and struck the southern tip of Sicily. They swiftly conquered the island, meeting very little resistance given that the bulk of the German forces had been moved away from the area. For the following two weeks the Germans continued to anticipate Husky landings in Sardinia and Greece that never came. By the time they realized that they had been duped, German forces had no chance to regroup effectively, and therefore retreated to Messina. Within a month, the entire island of Sicily was under Allied control.
In the intervening years there has been much investigation and speculation into the true identity of Major William Martin. Due to the findings of amateur historian Roger Morgan in 1996, the Man Who Never Was is now believed by many to be Glyndwr Michael, a Welsh vagrant who died after ingesting rat poison and subsequently suffering chemical pneumonia. The markings at his burial place have been updated to show Glyndwr's name on the tombstone, however not everyone is convinced that he really was Major Martin. There are some pieces to the story which don't quite seem to fit, such as the length of time between Glyndwr's death and the execution of Operation Mincemeat. Additionally, the HMS Seraph took a long detour before heading to the Spanish coast, causing some to suspect that it was retrieving a body from elsewhere, possibly one of the victims of an accident onboard the HMS Dasher.
Considering the deliberate efforts to protect the true identity of Major Martin at the time, and given the number of years that have passed since his death, it is quite possible that we'll never know his real name with any certainty. Whoever he was, his body certainly did an incalculable service for its country.