Different times, different rules. New Zealand was much closer to the UK at the time, and the US were using the fact that they had thermonuclear weapons and nobody else in NATO did to ensure they controlled the alliance at the time. Given that the expectation was that New Zealand would be under the UK thermonuclear umbrella (such as it was) after the testing - and also the US policy would have to become more accommodating - then it wasn't an especially unreasonable request. The British seem to have been a little put out at the refusal, but seem to have got over their disappointment very quickly.Thank God he did. If Britain didn't want to test nukes in their own backyard, why the hell should New Zealand agree to them (or anyone) testing them in ours. (Note: We were really annoyed by the French government for the whole Moruroa thing, plus their bombing of the Rainbow Warrior in the 1980s)
In any case, the mainland UK doesn't have any suitably remote sites - Kermadec is ~500 miles downwind of New Zealand itself, applying the same thing to the UK means adopting a test site in the USSR. The test site eventually adopted is a lot further from New Zealand, but that's mostly a pain in the backside for logistics - the chances of New Zealand being affected by the Grapple tests being conducted in the Kermadec islands instead is essentially zero, and it's worth noting that there were actually people living on Christmas Island before the testing, which isn't true for Kermadec.
Not mentioned in Britain and the H-bomb (Lorna Arnold), which is probably the best reference out there. The selection seems to have come from Selwyn Lloyd (the British Foreign Secretary) in May 1955, "after consulting departments" - this suggests that the people making the approach may not even have been aware that the islands were volcanic at the time.I wonder when they last thought there was volcanic activity there. A Dept of Conservation worker was killed by a small eruption in 2006.
The sequence seems to have been that they were identified as suitable by the Foreign Office, an approach was made to the New Zealand government and rejected. Some time after this (17th September 1955) three Shackletons were sent out from Northern Ireland to carry out a photographic reconnaissance of the favoured locations, which had changed to Malden & Christmas islands in the interim after a report had come back from the Acting High Commissioner in the West Pacific.
The original plan was that the testing would be ~500 miles out to sea, and a number of really obscure bases were suggested like the Antipodes Islands to support this plan. I suspect this may have been a reaction to the fallout from Castle Bravo landing on Daigo Fukuryū Maru the year before - figure the most remote islands you can think of, then carry out the test a long way from them where no shipping at all will be about.I mean, one can imagine worse places.
Like, say, the Piton de la Fournaise. Or the Anak Krakatau.
Interest in the Kermadec islands only started in OTL for the Grapple test series - the first (Short Granite) was 300kT, rising to 3MT for Grapple Y.But I don't think the numbers work out, especially since these early devices are going to be rather small (in the kiloton range). They're going to be good at producing an atmospheric blast wave but not nearly as effective at at shattering or vaporizing rock. Not good enough to breach the hundreds or even thousands of meters of cap-rock over the magma chamber.
Thanks. It's worth noting that a lot of the effects come from the community commenting on the timeline - I could never have written anything like this without their support.A month after discovering this timeline, I finally got to the last page of it. I've never read anything which goes into such granular depth to explore the effects of a point of divergence in so many ways. Saying this is par for the course for alternate history as a genre, but it's truly fascinating how different things would be if events played out even slightly differently. The timeline itself is the main course, but as much as I wanted to skip ahead I just couldn't stop myself from perusing the buffet of information other commenters have provided on a variety of subjects, from politics to international trade to military R&D. My knowledge of many of these topics is quite limited by comparison, so it has been incredibly educational to view the discussions which have spawned from this thread. I eagerly look forward to more and applaud the author for putting so much effort into an excellent piece of work!