[philipwhiuk]

AIUI, the difference in training is not that much in the UK between sidearms and machine guns, so anyone who is certified on one probably also has the other.

Whereas in the US, every cop is armed but there's more checks on the more strict stuff.

Your airport police want to be armed but there's no need for them to be heavily armed. So in the UK they all are, because it's the same people. In the US the heavily armed folk are deployed elsewhere (SWATing someone's Twitch stream if the media tells me the truth...)