Garbo - Juan Pujol Garcia

D-Day 6 June 1944 - Operation Overlord

At about 03:00 Garbo tried to inform Berlin that the Allies were about to invade Normandy and the attack was planned for 6am. (3 hours before the invasion was considered a good time because it allowed Garbo to keep his credibility by informing Hitler before the event, but did not give him any time to do anything about it) However, nobody was manning the post to receive the messages until 06:15 at which point the invasion was well underway.
There was a caveat with Garbo's message, being that this invasion was only a diversionary tactic to draw the German troops and Panza's away from the real invasion point of Calais that would begin as soon as enough troops had been distracted down to Normandy.
So trusting of Garbo was Hitler that he ordered that the full might of the German army to hold their ground at Pas De Calais waiting for the full invasion. (Which never came, well not at Calais.)

Berlin fell for this manoeuvre because of the information they had received during the previous weeks.
Garbo had informed them of the imminent arrival of an extra 100,000 American and Canadian troops.
He informed them of many tanks, planes and personnel carriers congregated in South East England preparing for the invasion.
Shortly after this particular information was given it was known that Berlin would instruct the Luftwaffe to send a reconnaissance plane over to confirm the tanks and planes etc.
The plan to confirm this was to make as many tanks and planes out of wood and other materials as possible and to secure them in fields in the south east.
This had been done prior to the messages being sent and as predicted the reconnaissance plane came over and was allowed to view the area's where the phantom army was congregated
Some fire was sent towards it but not intended to hit it.
While all this was going on about 400 men were talking on the radios pretty much constantly to give the impression of a large army in the area.
Garbo did not plan all this, but it's because Hitler trusted him so much that he went with what Garbo told him.

6th June 1944
Over 5,000 Ships
Over 1,200 Planes
Carried more than 250,000 men into the greatest military invasion in the history of the world.

A Major General found himself with a plethora of officers, but only three enlisted men. He told them, "Never have so few been commanded by so many."
But if confusion and disarray prevailed among our Paratroopers, it was even more in evidence among the German defenders. They still had no idea that the invasion had begun.

Having said that the Germans were still unaware that a full-scale invasion was underway there was still very strong resistance because the whole coastline was fortified with machine guns.
As the allies landed they were subject to an enormous amount of strafing and many men lost their lives before they touched dry land.
Had it not been for the fact that Garbo had completely fooled Hitler about the invasion, their would have been more than double the fire power against the allies and a lot more to come.
As I said before all this firepower was held back waiting for the invasion at Calais.
By nightfall there were 150,000 allied troops ashore and thousands more on their way.

DDay message that Garbo transmitted to Berlin
(Translated to English)

"I never like to give my opinion unless I have strong reasons to justify my assurances. Thus the fact that these concentrations which are in the east and south-east of the island [Britain] are now inactive means that they must be held in reserve to be employed in other large scale operations. The constant aerial bombardment which the area of the Pas de Calais has suffered and the strategic disposition of these forces give reason to suspect an attack in that region of France which at the same time offers the shortest route for the final objective of their illusions, which is to say, Berlin.

"Which advance could be covered by a constant hammering from the air since the bases would be near the field of battle and they would come in behind our forces which are fighting at the present moment with the enemy disembarked in the west of France."

November 1943 Franklin Roosevelt, Winston Churchill, and Joseph Stalin got together at the Teheran conference.
They discussed the outline of the deception codename Jael but then changed the codename to Bodyguard.

Bodyguard could be broken down into 5 deceptions. Vendetta and Ferdinand were false invasions in the western Mediterranean, and Ironside was an invasion of France from the Bay of Biscay. Zeppelin was a false invasion of the Balkans. The final deception was Fortitude, which could also be split into 2 sections North Fortitude & South Fortitude. North Fortitude was a false invasion of Norway and South Fortitude was the false invasion of Pas de Calais in France.
Garbo had to give all this deception to Berlin in manner that they would totally believe. This involved feeding them some true information as titbits to enhance his credibility.
The information was chosen specifically, it would be information that had no real benefit to Hitler or it would be information that the Germans were about to discover but before the German forces could report it Garbo would get in first. Field Marshal von Rundstedt specifically cited "Garbo's reports in meetings he had with Field Marshal Keitel.