Sunday, August 19, 2018

The Dieppe Raid and blown intelligence

German photo of Allied dead at Dieppe
British intelligence told the Germans in advance of the Dieppe raid

On this day in 1942, a force of 4,963 Canadian troops, accompanied by just over a thousand British soldiers, 50 US Rangers and 15 Frenchmen, conducted the catastrophe of Operation Jubilee.

Known to history as the Dieppe Raid, the outcome of the brief assault against the French, German-held port of Dieppe was a decisive, bloody defeat of the Allied forces.
At Dieppe, 907 Canadians, including 56 officers, lost their lives in a battle that lasted for only nine hours. A total of 3,369 men were killed or wounded. At Dieppe, the Canadian Army lost more prisoners than in the whole eleven months of the later campaign in North-West Europe, or the twenty months during which Canadians fought in Italy.
Why did the raid take place?


Allied planners had agreed that an actual second-front invasion of occupied France could not be undertaken without substantially more experience. Though successful, the landings against Vichy French forces in northern Africa were certainly no rehearsal for operations against Nazi forces on the French coast.

So the Dieppe raid was born. The raid had no long-term tactical objective; even had the raid been entirely successful., Dieppe was to have been abandoned and troops withdrawn to Britain after a short time. The raid's goals were entirely strategic, oriented toward the future invasion of France from the sea.

Jubilee's main objectives were to train leaders at all level to conduct large-scale amphibious, combined and joint operations against the coast of France, to seize the port and hold it for a short time, to take prisoners and gather intelligence, and to demolish certain German fortifications.

It was in short meant to form the basis of an extensive set of lessons learned that could be applied toward invasion when invasion came, and to boost home-front morale at a time of the war when little could be cheered in European fighting.

The Raid

Carried by 240 Allied vessels, the raid was late in getting started, a day late in fact, having originally been scheduled for Aug. 18. The first troops to land had to advance in dawn's light rather than darkness as planned. Consequent loss of surprise is still held to be a primary reason that the raid was repulsed so bloodily. In fact, the Allies had utterly lost the advantage of surprise, but the loss was not because of daylight; it was because of the postponement. German forces were fully alerted and aware of the coming raid before the first ships appeared over the horizon.

There were two supporting, prior attacks on the east and west of the main line of advance, commencing at 0500 hours. Both were thrown back quickly with great loss. Because of this, the Germans were able to bring fierce, effective fire directly upon the main force when it landed opposite Dieppe.

Landing at 0530 hours, the main force was immediately taken under intense small arms, mortar and artillery fire. Despite the heroism of the attacking troops, a bare few made it off the beach. Twelve of 27 Canadian tanks were knocked out before getting off the sand. Only six reached the beach's esplanade, where they were stopped by antitank ditches and then destroyed.

Six hundred Canadian reserve troops were landed when commanders mistakenly thought that the initial troops had taken a foothold in Dieppe. They suffered all the way onto land and 475 of them never made it back to England.

Hardly anywhere did Allied troops make it much more than a few dozen yards away from the waterline. Only Number 4 Commando of the Royal Marines achieved all its objectives of the day, and those were very limited, though difficult to be sure. At 1050 the order to abandon the attack was given.

Why the attack failed

Loss of surprise on the morning of the attack is usually attributed as a main reason the raid failed. Yet the real reason the attack failed was revealed in 1963 by Stanley Lovell, chief of research and development of the American Office of Strategic Services during the war. The reason was very simple: Britain's Secret Intelligence Service ("Broadway") told the Germans about the raid a day ahead of time, on purpose.

In chapter 15 of his book, Of Spies and Stratagems, Lovell relates the story of a German spy captured in Britain on Aug. 31, 1939, who under interrogation claimed that his lineage was of "almost nobility." Before long, the SIS and the German came to agreement: he would be doubled to work for the SIS and after the war was won Britain would make him a knight of the realm.

Lovell says he personally read many of the messages to the German espionage service that the would-be knight sent, many of which critically misinformed the Germans of Britain's readiness to repulse invasion or of the combat depth of the Royal Air Force.

A precursor to the misfired Dieppe stratagem was a commando raid against the island of Lofoten, where German occupiers produced large quantities of fish oil used in explosives. The doubled agent radioed the Abwehr that the islands would be attacked on March 6, 1941. Germany rushed forces to the scene only to find two-day old, charred ruins and a sign poked into the sand that said, "We'll smoke your fish for you!"

Three months later a similarly accurate-but-late message was sent warning of a commando raid against the French port of St. Nazaire, where the destroyer Campbelltown, loaded with explosives, was remotely crashed into the only drydock along that coast large enough to handle German U-boats.

The SIS was given permission to send just such a too-late-but-true message to the Germans about the Dieppe raid. The message was to be sent Monday evening the 18th of August, about 12 hours after the Allied forces had landed.

The SIS was not told that the landing was postponed until Tuesday. The Germans received the message Monday evening, alerted their forces at Dieppe and were waiting before dawn on the 19th.

Lovell writes that a director of Britain's Special Operation, Executive told him that the SIS operation escaped being closed down by the thinnest of margins, surviving only when a Briton pointed out that the doubled agent's standing with the Abwehr could not possibly be higher, and that the Germans would now believe anything he told them.

Claiming to have very highly-placed sources deep within General Dwight D. Eisenhower's headquarters, the agent became deeply involved in deception operations covering Operation Overlord, the invasion of France in 1944. Most important was to deceive the Germans of the place and time of the invasion. I'll let Lovell finish the story (click for larger image):

The aftermath The raid was a disaster for the Allies and a propaganda triumph for the Germans. Lovell writes of the sickening feeling Allied commanders had when viewing captured German reels of the battle.

As you may imagine, finger pointing among British commanders and the imperial staff began almost immediately. Lord Louis Mountbatten, the attack's main advocate, maintained the rest of his life that lessons learned from the raid were invaluable for later Allied successes. These arguments are weak, according to the BBC:
The disaster did point up the need for much heavier firepower in future raids. It was recognised that this should include aerial bombardment, special arrangements to be made for land armour, and intimate fire support right up to the moment when troops crossed the waterline (the most dangerous place on the beach) and closed with their objectives. 
However, it did not need a debacle like Dieppe to learn these lessons. As judged by General Sir Leslie Hollis - secretary to the Chiefs of Staff Committee and deputy head of the Military Wing of the War Cabinet with direct access to Churchill - the operation was a complete failure, and the many lives that were sacrificed in attempting it were lost with no tangible result.
Canada at War disagrees with the BBC's assessment that nothing worthwhile was learned at Dieppe.
The Dieppe fiasco demonstrated that it was imperative to improve communications at all levels: on the battlefield, between the HQs of each unit, between air, naval and ground forces. The idea of capturing a well-defended seaport to use as a bridgehead was dropped after August 19th, 1942. In addition, the raid on Dieppe showed how important it was to use prior air bombings to destroy enemy defences as much as possible, to support assault troops with artillery fire from ships and landing crafts, to improve techniques and equipment to remove obstacles to men and tanks. 
The true meaning of the sacrifices made at Dieppe was made obvious two years after this ill-fated date, when on D-Day the Allies gained a foothold in Europe to free the continent from Nazi aggression. 
Canadian General H.D.G. Crerar says D-Day would have been a disaster were it not for the lessons of Dieppe. Among those lessons: don’t assault a fortified fort; rather, attack on the beaches, give infantry support and plan it all down to the last hand grenade.
This seems a better assessment to me. Perhaps these lessons would have been learned otherwise, but perhaps not. For sure they were learned that day. Just as importantly, the British and other Allies took to heart that there had to be a seamless integration between military, intelligence and counterintelligence operations. This was just as valuable a lesson as any of the military ones.

Finally, Global News Canada says that raid's magnitude was a deception operation aimed to mask the raid's true purpose: to "pinch" (capture) a new version of the Nazi Enigma encryption machine.
According to O’Keefe’s research, British naval officers used Operation Jubilee to target the German-made Enigma code machine, an electro-mechanical piece of equipment that used a series of rotors for the encryption and decryption of secret messages. ... 
While the British were successful breaking into the three-rotor Enigma machines, everything changed on February 1, 1942, when the Germans introduced the four-rotor Enigma device — instantly blacking out Bletchley Park. 
According to files, British naval intelligence believed that in order to crack the four-rotor Enigma machine, a pinch raid was necessary. A successful pinch would mean secretly stealing parts of the machine, code books and setting sheets.
This may well be true, with the other objectives listed above being also true, but of lesser strategic importance. It doesn't change the fact that the SIS blew the secrecy of the whole show.

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