It got worse when not on home soil, the Brits were not adverse to atomic test fallout drifting across Australian cities and indigenous populations, nor to secretly beefing up weapons to make them more radioactive while claiming not to have done so.

In an interesting foot gun case, they got their own (future) Prime Minister:

    British Prime Minister Tony Blair is one of thousands of people reportedly at risk of bone cancer after a radioactive fallout in Australia in 1956.

    British medical researcher and toxicologist Dick van Steenis told The Bulletin magazine Mr Blair was likely to have residue of strontium-90 in his bones and bone marrow from his time in Adelaide as a three-year-old.

https://slwa.wa.gov.au/stories/slwa-abc-radio/montebello-isl...

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