If you need to import arms you've already lost. The moment the tea binging subjects let their masters take their guns was the moment they surrendered totally.

The british nationals have over time been stripped of the will to liberty. Over hundreds of years of colonial efforts and emigration, nearly every line of people with the mental fortitude to handle being a citizen instead of a subject has left, to the US or other colonies, or been killed in war.

The genetic and cultural remnants of the british nation are no longer capable of freeing themselves.