Most "officers on the beat" don't carry guns, but perhaps as a sorry sign of the times it is not uncommon to see officers packing what appear to be quite heavy weapons (at least to my eyes) - e.g.:
You'll see them at busy places like stations, shopping centres, airports, busy public squares etc. At least in London - perhaps not so much elsewhere. I guess half of it is deterrent & reassurance, and the other half if to stop any "active shooter" type things before they happen.
There is also SO15 which are the sort of para-military dedicated anti-terror type people who don't patrol but are stationed around the place and use motorbikes to cut through traffic and down pedestrian areas, e.g.:
I think the main difference in the UK is, when the situation deteriorates enough to require police with guns turn up, the guns aren't there for show to try and subdue/persuade you. They'll usually shoot to kill from what I've seen/read/heard.
Get outside of central London (and possibly some other big cities like Birmingham? I don't know, I never go there) and you'll never see armed police anywhere. I grew up in a small British town in the Southeast and I can't think of a single time in my entire childhood that I saw a police officer with a gun (or for that matter, anyone else with a gun) anywhere near my hometown, except perhaps for my rare visits to touristic hotspots in London. And again, it's only in central London, at least as far as I can tell. I live in non-central London now (Zone 3) and I never see armed police anywhere near where I live. Come to think of it, I rarely see any police at all around here, at least not on foot.
I can remember going on holiday to France as a kid and being unable to take my eyes off the guns I saw on the hips of French police, because it was such an unusual sight for someone born and raised in middle England.
I think in the UK we're so used to the idea of unarmed police that we forget how astonishingly unusual it is. In most countries the idea of unarmed police is unimaginable. We've really achieved something special by managing it, at least in most parts of the country most of the time.
https://i.dailymail.co.uk/i/pix/2015/04/26/11/22FFD9CC000005... https://qph.fs.quoracdn.net/main-qimg-0fe4637f8d1b1f981c7786...
You'll see them at busy places like stations, shopping centres, airports, busy public squares etc. At least in London - perhaps not so much elsewhere. I guess half of it is deterrent & reassurance, and the other half if to stop any "active shooter" type things before they happen.
There is also SO15 which are the sort of para-military dedicated anti-terror type people who don't patrol but are stationed around the place and use motorbikes to cut through traffic and down pedestrian areas, e.g.:
https://i.dailymail.co.uk/i/pix/2017/09/28/10/44C62468000005...
I think the main difference in the UK is, when the situation deteriorates enough to require police with guns turn up, the guns aren't there for show to try and subdue/persuade you. They'll usually shoot to kill from what I've seen/read/heard.