This is a short but very good video.
I think that the main reason for British firearm regulations in 1920 was due to the threat of Communism and Socialism that was running rampant through the continent.
Even in the USA there was a major uprising in the coalfields. https://en.wikipedia.org/wiki/Battle_of_Blair_Mountain
The Battle of Blair Mountain is a very interesting study involving citizens on both sides arming themselves and going forth to fight.
Ludlow...