Aethelstan (924) was potentially the earliest ruler who had authority over the mainland UK after defeating the Scot’s and Welsh and having them acknowledge him as ruler of the whole island. He confirmed this at Brunanburh when he defeated a Scot’s / Viking army. He died without issue and quite...
Except ensure the Nazis were beaten may possibly have been a benefit to the UK and humanity as a whole? Especially ensuring it was a victory that didn’t involve the Red Army occupying what was left of Europe.
Given the IRA at this point was completely penetrated by the security forces can’t see that as a major worry, and that given the Sikh community in the UK has never been a particularly political one so active terrorists are likely to be a very small group I just can’t see this becoming an issue...