Even an Australian, Mark Oliphant, acting on behalf of the British MAUD Committee,, played a highly significant role in the bombs development. Certainly a multi national effort.

https://en.wikipedia.org/wiki/Mark_Oliphant

https://en.wikipedia.org/wiki/MAUD_Committee

There's an interesting (and possibly false story) That there is an office in Manchester Uni that has a strange cancer rate that Rutherford worked in.

For some more information about early atomic bomb research pre the Manhattan project see the following:

https://rhydymwynvalleyhistory.co.uk...alleyworks.htm

All kept secret until relatively recently, though many locals worked there.

IMHO, Jim Baggotts book is by far the best I have found on the topic. Also covered off the deals between UK and US during this timeframe.

Well worth a read, not least to learn of Fuchs involvement in Russian Spy rings from that time, activity that saw the Rosenbergs executed for similar activity in the USA (the went to the chair).

Quite a dit on the UK Tube Alloys programme on Wiki.

https://en.m.wikipedia.org/wiki/Tube_Alloys

Rutherford would have been astonished to see himself spoken of as other than British And had he conducted his research with the facilities then available in NZ we’d never have heard of him. As a result his former lab at University of Manchester is still slightly radioactive!

Leo Szilard was a naturalised Brit. If anyone can be said to be the 'inventor' of nuclear weapons and nuclear power, it is he.

He patented the idea of nuclear weapons and handed ownership of that patent to the Admiralty of his adopted country.

Rutherford scorned the idea, mocking it by saying that anyone who believed in nuclear power was "talking moonshine".

I can recommend "Test of Greatness", by Brian Cathcart; an entertaining and informative account of the development of the British bomb. A fascinating mix of science and fumbling.... I've just looked at the current prices, and will now carefully dust off my copy(!)

For TTN.....
 

......its OK matey, having known oxenos for a looooooong time I don't need the said search engines translate tool to understand him. And he IS a pilot but an amiable one.
(However he has been known to wear Empire Builder KD shorts in furrin parts. Which caused a mixture of dismay and hilarity in equal measure during an enforced stopover in Istres) Also a looooong time ago.

The Ancient Mariner

Don't forget Dr Francis Simons (later Professor & Sir) a naturalised Brit, I know, who invented Uranium gaseous diffusion separation process one Saturday morning in June 1940 using a tea strainer, a bicycle inner tube and sealing wax. He demonstrated it's practical application by separating H2O vapour from CO2 gas in time for inclusion in Tizards mission to the USA in the autumn of that year. At the time the US had relegated the atomic bomb to a 20year "academic " project at least in part because nobody had figured how to separate the active ingredient. Now although it's generally credited that it was Einstein's letter to Roosevelt which kicked the project to super priority the fact that someone had cracked one of the key show stoppers must have meant something......surely.

Francis went on to pioneer Gaseous Diffusion at
Rhydymwyn Valley in north Wales and latter Oakridge.

The Brit team that cracked the implosion Pu bomb were Chadwick, Tuck, Taylor, Peierls, and Frisch.......uh and Fuchs. They took the job on when it was generally considered to be a dead duck;- It had been offered to the best American guy they had, Teller (well a naturalised American ) who declined, so it went to the British Mission who were at the time "a bit out of place" but keen to show what they could do. What was achieved in a stupidity short timescale was simply astonishing.

Nonsense. My KD was made by that master craftsman Tong Hoe of Changi Village. You must be thinking of two other fellas.