[Ex gun maker.]

RE: The Brits have few arms.
The precedent has been seen, just ask Nicolae Ceaușescu.
It is amazing how quickly a populace can produce weapons for themselves when they have finally had enough of tyrants.
Once the the military begins defecting to the defense of their parents, siblings, and children the outcome is set.

[Billthedrill]

That's exactly right. The notion that the UK is disarmed is really not quite true - regular smuggling routes from Eastern Europe that pass drugs pass other things too, and Islamic terrorist organizations have great experience doing so as well. The Guardian reported on this quite some time ago, and an estimated 978,000 unregistered firearms were believed to be in circulation in England, Scotland, and Wales as of 2018. (Brave AI)

That number will likely not have diminished since. It's almost as if when guns are outlawed, only outlaws...

[MtnClimber]

Very good point. And the military that don’t defect are still a source of weapons.