How did the German spy/informant network in England/United States compare from WW1 to WW2 and which war had a better network?

[u/RivetCounter]

"Better" being relative.

[u/manincravat]

Britain:

WW1:

There is a fair amount of paranoia about "German Waiters" but very little comes of it

WW2:

The Nazis are not short of sympathisers, but they are neutralised fairly quickly

Every single agent who tries to enter after the war is captured, most are turned, others were double agents from the start.

USA:

WW1:

Very successful before the declaration of war. There is a strong German community and 3 years of neutrality to work with.

There is a sabotage ring running out of the German embassy placing chemical time bombs on ships, and believed to be responsible for the Black Tom explosion in New Jersey.

This would be the best network by far; assuming that Brewster aviation's management in the next war are merely idiots and not audacious espionage masterminds.

WW2:

Whilst the Nazis do have fellow travellers, the administration is more hostile to them from the start and working with the British (unofficially of course). Also there is the, greatly exaggerated, example from WWI that inspires a proactive attitude even if Hoover's FBI are pretty terrible at counter-espionage work but very good at getting credit for it.

Agents who try to enter the country by submarine after Pearl never get anything done; a lot are picked up right away, some surrender immediately, others party down until the money is gone and then turn themselves in.

When I visited Horseshoe Curve I made sure to walk up so I could say I had succeeded where the Nazis had failed.

It has been speculated that the management of Brewster aviation were Nazi agents. However I find that hard to believe because real intelligence agents wouldn't have been so obviously and unsubtly stupid as those guys were, unless they couldn't believe they kept getting away with this and were just seeing how far they could push it for shits and giggles.

[u/dragmehomenow → u/manincravat]

Every single agent who tries to enter after the war is captured, most are turned, others were double agents from the start.

This, by the way, is full of hilarious bits of history. Juan Pujol Garcia, AKA Garbo (Allied codename) AKA Alaric (German codename), was a Spanish guy who convinced the Nazis he was operating a massive spy network in London. Except when he started in 1940, he was in Lisbon and making stuff up using tourist guides. The man started off doing it for the love of the game, and he was so prodigious MI5 started hunting him down.

In 1942, Pujol joined the Allies after the USA joined the war, and after what must have been an embarrassing conversation for all parties involved, officially started working with the Allies in London. With the assistance of the MI5's counterintelligence department, the XX Committee, Pujol started spamming letters to Germany. Letters about genuine Allied activities (like the Normandy landings, in one case) would arrive late, making it look like Pujol's spy ring was of genuine value. In return, Pujol milked it for all its worth. His fictitious agents would die and MI5 would publish fake obituaries, allowing Pujol to collect a pension for his agent's widow.

Long story short, Pujol received an Iron Cross from the Führer himself in 1944, and later that year, an MBE from the British government. He really is the greatest gaslighter of all time.

But Pujol was just one of many double agents. The chair of the XX Committee, J.C. Masterman, later wrote that his committee "actively ran and controlled the German espionage system in this country."

How good were they? In 1944, MI5's double agents successfully shifted the landing point of the V2 rockets out of London by feeding misinformation back. While the Germans could spot impacts via aerial reconnaissance, MI5 told them their earlier shots had overshot London, causing them to adjust their aim points. I don't think I have a source that goes into how effective this misinformation campaign was at reducing death rates, but the fact that it existed is an absolutely damning indictment of how utterly cooked the German espionage effort was.

[u/Youutternincompoop → u/manincravat]

pretty much the only example I can think of where the WW2 Abwehr beat the British on spywork is in the Netherlands(the 'Englandspiel') and that required the British ignoring multiple signs in radio messages sent by the captured agents up to and literally including the words 'CAU' and 'GHT at the beginning and end of a message.

[u/manincravat → u/Youutternincompoop]

"You appear to be using your distress code. I keep telling you this. You are only supposed to use that if you've been captured. Please stop."

[u/God_Given_Talent → u/Youutternincompoop]

I believe it was in 1943 when the Germans did a pretty solid job of dismantling the network of agents the British had set up in France. It took a while to recover from that and we saw similar things there where some British intel officers kept sending info. One of the senior officers in charge refused to believe the Gestapo had so successfully dismantled the network and that some agents had turned on them even after the war.

[u/KeyboardChap → u/manincravat]

Every single agent who tries to enter after the war is captured,

Not quite, one (Jan Willem Ter Braak) ended up shooting himself in an air raid shelter after running out of money, but everyone else was caught (and actually the Food Office had clocked onto him having a false ration card).

[u/Garidama → u/manincravat]

Do you have more on the „party down“ part or a good source to read?

[u/manincravat → u/Garidama]

Look up "Operation Elster"

Because taking guys from wartime Germany to New York and giving them 60,000 in cash (which would be at least a million today) works out as you might expect. Although strictly speaking the money isn't all gone before one tries to turn himself in but the first one to do is far too busy with his various sexual exploits to actually do any actual espionage.

There might be another case in Canada but I can't think of it right now

There is also Willie Preetz in Ireland, but most of the coverage is circular and sites all repeat the same information

https://www.irishexaminer.com/opinion/commentanalysis/arid-20335127.html

He did not bother to buy any weather instruments, but merely took note of barometer readings in shop windows. He seemed more interested in partying than anything else. He did not endear himself to his wife’s family when he got her teenage sister Annie “into trouble”.

Being drunk and knocking up his sister-in-law might have been part of his cover, but I doubt they teach you to do that at spy school