Well, I should have been more emphatic about it being a theory. I've never even been to England, not that a short trip would give me a good idea anyway.

Regardless, there's a huge difference between the cultures of the US and the UK in regards to guns, whatever the reason. Just the fact, as you point out, that cops in the UK don't carry guns but that that same idea would be ridiculous in the US is strong proof of this.