Wasn't Operation Fortitude a terrible idea?

So reading a little on the amazing story of the operation Double Cross and the related disinformation operations of WW2. Its an amazing story (I’m amazed it hasn’t been made into a film), but the thing that stands out to me is how incredibly risky Operation Fortitude, specifically Fortitude South was.

I mean it worked so its a pretty pointless debate (hence why IMHO) but surely all it would have taken to both blow the operation, and make quite clear to the Nazis that D-Day was not destined for Calais, was one real agent (or overflight, though presumably little chance of that) who could confirm there weren’t 100,000s of thousands of allied troops in Kent.

It wouldn’t take a mole in the higher echelons of allied command, a single barmaid or bus driver who was actually a German agent, out of the millions of people in the South East England, could confirm that there were basically no troops in SE England. And the allies knew that, as that is exactly who most of their fake Double Cross agents, were. We know in retrospect that the double cross agents run by the British made up all the agents the nazis had on the ground (or thought they did, at least, most of them didn’t exist IRL), and they trusted them completely. But at the time surely they had know way of knowing that?

Admittedly had the Enigma and Lorenz decryption to check the results of the deception, but that was only after the fact. Presumably a barmaid in a small town in Kent, would not feature very prominently in the communications of the German intelligent services, until they made a discovery like this. What would have happened in May 1944 if suddenly there is an “agent Bardame” (maybe confirmed by another “agent Lastwagen”) stating 100% there is no way there is an army group in SE England.

I suspect they would have considered the confirming agents to be double-agents trying to trick them, wouldn’t they? That’s the genius of turning most of your enemy’s agents: the ones you don’t turn will look like the turncoats.

Surely that’s only with hindsight we know that. At the time they had no way of knowing that. And planning an entire operation on that supposition, where the downside is to basically reveal to the Nazis where D-Day is going to happened is a really bad idea? I mean if you rule out Calais you only are only left with Normandy (I don’t think anyone seriously thought the main invasion was going to be in Norway or south of France)

I’m not sure I’m clear on what “that” and “they” mean in this quote. Not trying to be difficult. If you mean “It’s only with hindsight we know that [the majority of Nazi agents were working for England],” I somehow thought England was confident of that at the time. Am I wrong?

Surely its only with hindsight we know that the Germans were 100% taken in by Double Cross and would have probably thought that a real agent’s reporting the truth was a double agent, not the fake Double Cross reports.

But the British Intelligence services in 1944 had no way of knowing that. There were some promising signs in what they read in Enigma and Lorenze decrypts, but to extrapolate from that to saying there is no way the Germans have enough real assets in the UK to blow operation Fortitude seems a big leap. Again, it wouldn’t take a mole in Eisenhowers HQ, it would be obvious anyone in the South East of England that there aren’t 100,000s of troops there. That number of troops can’t be kept secret.

I just got finished reading that book! As I recall, there’s a section where it details that the people in charge of the XX committee worried about that, but evidence from Ultra intercepts confirmed that the Germans had no agents in GB who weren’t either working for the Brits or entirely imaginary (and working for the Brits).

Okay, I think I see what you’re saying. And I’m about as far from an expert on this as a person can get, so if I’m speaking out my ass I welcome correction.

But it seems to me that they don’t need to be 100% certain to move ahead. Espionage rarely allows 100% certainty. Instead, they were doing the best they could in this regard as part of a multilayered attack plan. The better this aspect did, the better the military’s chances would be when they attacked at Normandy.

It turned out that they rocked this plan, but if they hadn’t, would the military have done anything differently–besides been a lot likelier to fail?

And remember, through both overflights of their own by US & RAF forces and the Ultra intercepts, we knew where ALL of the German forces were. All of them. They’d have known things were blown as soon as the Germans started moving soldiers and tanks to counter a landing at Normandy, which they would have had to do well before the landing date to be effective.

Yeah thats the thing. It seems like the whole of D-Day would have gone very badly. Remove the imaginary threat to Calais and you have enough troops in Normandy to jeopardize the landings. And that’s what fortitude would have done if it failed. They could have done what generals usually do in a situation like this, put actual some troops in the SE of Engand. Obviously that makes D-Day less likely to succeed, but still more likely than if the Nazis knew for certain it wasn’t Calais (anyone can tell a 100 people aren’t a full army group, but 10k people could be, especially if they move around a lot.)

Yeah but Fortitude kind of relied on 100%, a single barmaid in German employ could blow the whole thing.

But that’s what I’m saying. If the British were pretty sure that they had a bunch of German spies in their employ, then they could be pretty sure that a single spy not in their employ would look unreliable.

One of the ways that spy agencies avoid double agents is by cross-referencing information. If they have 10 spies saying, “Oh shit there’s a crap-ton of troops in SE England,” and one spy saying, “Gee, there sure aren’t many troops in SE England,” why would they believe the one spy over the 10?

British intelligence knew that the Germans had been fooled by the phony spy network that had been set up in Britain. There was always a chance of an unsuspected German agent (supposedly none were landed in England after 1942) or a domestic turncoat somehow revealing the truth, but the Germans would then have had to choose between believing a large and trusted organization, or an isolated spy or two who might be planting false information.

At any rate it’s a great success story for British intelligence, whether or not they were helped by Canaris and allies sabotaging German spy efforts.

Keeping them guessing can be pretty effective too, though.

And a barmaid or two as against all the faked radio traffic? Plenty to keep them uncertain there.

I think this was the big key along with reconnaissance overflights; they could tell if the Germans were mouthing the bait, had been hooked, or had swallowed it completely, just by using these tools.

Dumb question, but why couldn’t the Allies have massed huge amounts of troops in southeast England - half, or all, of the eventual invasion force - but have them set sail for Normandy instead, departing from SE England? Too far?

It would totally make it seem to Germany that Calais was the intended landing site, up to the point where the ships set sail.

Across from Calais is too close to Calais. The sea lanes were choked with mines, which were cleared ahead of the Normandy invasion. And several air missions to clear coastal defenses and establish air superiority. Setting off from Calais would require a diversion of minesweepers and air power that would have unnecessarily incurred risk and loss of material.

Also, the jig would have been up almost immediately and the 15th German Army could have moved over very quickly. Part of the delay on the Germany side was the threat of an invasion at Calais. Without that threat, they could concentrate forces in Normandy much faster with superior interior lines of communication. Remember, the Germans kept significant forces at Calais under the premise the Normandy landings were a feint and did not take action until it was far too late. That would not have happened if they knew Calais wasn’t the real target.

Also, they did have some troops in SE England. Not enough space for the entire invasion force otherwise. But they did not set sail from there. It would not have made much sense. The only good reason, considering the massive logistical issues of a forced landing, would have been an actual invasion at Calais.

I thought a major part of the deception was deliberately sidelining Patton and making it seem like he was the Invasion Commander and was somewhere other than Normandy. Iirc Hitler said that even the Americans wouldn’t be so stupid to not make their best General the leader of the invasion despite his recent problems.

German High command, April 1945: it’s only with hindsight that we see we should have gone with that one barmaid’s report.

I think you underestimate the depth of the deception.

Mutt and Jeff were also sending detailed reports about the fictitious British Fourth Army in Scotland that was to join with the Soviet Union in an invasion of Norway.

A few trucks driving around the lanes of Kent could easily fool a barmaid into believing that they were part of a much larger force and even then she would have had considerable difficulty sending the information to anyone who could make use of it.

It would be interesting to know how much the local civilians actually knew. did they know that the tanks were fakes? How would they know that what looked like an army camp only had a few soldiers?

Such was the paranoia, whipped up by the government, that a putative spy, lurking in the hedgerows and hop gardens would probably have found themselves on the wrong end of a shotgun in short order.

There were lots of troops in the South of England. Actually all over Great Britain and Northern Ireland.
The issue for the deception wasn’t as much convincing the Germans as to the troops presence , it was as to their purpose. The most pertinent question for the German intel was, which troops are going to undertake the invasion (landing and follow up). if you have a heavy concentration of troops near certain ports that would give you an idea as to the likely destination. If troops are embarking in Plymouth, they probably aren’t going to Calais. So, you don’t need a barmaid to be a tattletale, that will be obvious. The Germans can read a map and they can see that Normandy is the most likely place such a force would land.
So, you do the next best thing, you convince the Germans that this is just a diversion, that the real effort would come elsewhere. The way they did was as the OP says, they created fictitious formations, however while the formations were often fictitious (not always as we shall see) the troops assigned to them were usually real. Who were they? They might be rear training echelon troops, training establishments, or troops designated for post Normandy operations, like the US 9th Army (entered combat in September 1944). Even the fictitious formations were often based on real ones, the staff of the 1st Army Group was what to have become Pattons Third Army.
The OP’s barmaid won’t see a lack of troops quite the opposite actually. Marry that with radio traffic and notational formation HQ, manned by actual staff and support elements and yes, actually the Germans could be and were fooled.

Don’t forget that from April 1944, there was a restricted zone stretching 10 miles back from the coast, right along the south coast, and large staging areas for invasion troops were closed off. Agents from elsewhere would have found it difficult to impossible to get anywhere near, and our putative barmaid wouldn’t have been in a position to know who or what was or wasn’t behind barbed wire without drawing a lot of attention to herself.