I love how one of the articles on the HN frontpage says "Oxford", the other says "European researchers"
-- Wikipedia
So the reason it is called European is that it was conceived by the EU and it's partners and it primarily funded by the EU's Horizon 2020 funding programme.
[0] https://web.archive.org/web/20170830004728/http://horizon202...
Or will this fusion go out of control and demolish the UK in a nuclear fireball?
It's probably related to brexit in that this outlook is very likely at least part of why Brexit happened (or rather why the UK was never a particularly good fit for the EU)