Well there was a Ju-88 which mysteriously landed at the RAF base next to Newcastle upon Tyne, disgorged a passenger and then flew off again in August
or September 1943.
Suppose this six-engined bomber had landed in the US and some kind of super secret treachery had been discussed, wouldn't that pee in the pool of
"the special relationship" between the US and the UK?
Since you mention it, at the Tehran conference Roosevelt and Stalin agreed that their two nations would run the post war world and dismantle
colonialism including the British empire.
General Leslie Groves authorised the export in several smaller shipments of 450kg of Uranium oxide to Russia. These shipments went via Peruvian
freighters from Seattle to Vladivostock and the Japanese dared not molest them.
Later in the war the SS John Barry was part of a special convoy to Persia where lend lease goods would be shipped to Russia.
SS John Barry was sunk off Oman by U-859, with a highly top secret cargo. Long after the war a French deep sea expedition was launched to recover her
cargo from greater depths than any recovery ever before.
The recovery cost more than recovering the Japanese ship Ehime Maru off Hawaii and almost as much as recovering the Soviet nuclear sub K-19. What was
aboard John Barry that was worth that efforts and expense ?
A clue is that in WW2 the Germans converted three Heinkel He-177 bombers with extra large bomb bays for the Nazi A-bomb. One of those airframes became
a donor fuselage for the Ju-287 V1 jet bomber.
The Ju-287 V1 was test flown through August to October 1944 when test flying suddenly stopped.
The reason why is evident from what General Walther Dornberger told another General in a bugged conversation at Camp 11 after the war.
Dornberger mentioned that in October 1944 he and Werner von Braun, of V-2 rocket fame went to Lisbon for talks with two officials from General
Electric Corporation. Dornberger also says he stayed in touch through December 1944.
Now Dornberger at that time worked for the SS in one of the most top secret Nazi weapons projects, yet he was free to talk with Americans in Lisbon
Give me a break !
However Dorneberger's boss SS Lt General Dr Hans Kammler shielded the Nazi nuclear scientists and Penemunde rocket scientists when Hitler ordered
their execution. He smuggled them south to Bavaria where the SS allowed the ALSOS mission to come and collect them.
In October 1944 Gen Leslie Groves removed Germany from the SBS list of nuclear targets for the Manhatten Project. Much more than co-incidence.
The German nuclear bomber project was abandoned. test flying of the Ju-287 jet bomber stopped in October 1944.
Von Braun and Dornberger it seems saved Europe from becoming the world's first nuclear battleground.
Now there's a good Tom Clancy novel for ya!