*comes out of lurking*
Just to add a little wider perspective here, and no doubt start another impassioned strand of debate... but like a few posters here, I grew up in Nottinghamshire too, and perhaps the main cause of violence in that city, although indirectly, was that Margaret Thatcher deliberately destroyed the Mining Industry which was Nottingham's main employer. And with mining went all the support industries that went with it... catering and entertainment (christmas jumble sales at the different "Miners Welfare" bars, I remember those!) transport of workers and goods... the latter was also massively and negatively affected by the further privatization of British Rail, which added huge costs to trying to move any heavy freight about the rail network...
Thus there was huge unemployment during my youth, parts of the outskirts making it onto the UN Emergency Development List it got so bad... and with it came the usual squalid after effects of poverty, violence being the most obvious one. Not just in the day to day, hauling off on someone who spilled your pint in the pub, or the missus for giving you lip when yer got 'ome, but also the usual political violence that comes with the associated the rise of the hard right in downtrodden areas; I can still remember the National Front graffiti scrawled on the side of the old railway bridges, unwashed for decades...
And I can remember when that policeman was killed in the middle of the city centre, by a cash point I'd used just a few days before... and the debates about how Nottingham was going to be the second force in the country (after the Met) to have armed police on permanent street duty, that that was when I realised just how rotten it could be back home... But, there were still two trends which kept even Nottingham from becoming a Wild West Town; I generalise because of course even expert, let alone amateur sociology is an inexact science to say the least!
The first was culturally specific to that particular area. If you've ever read any DH Lawrence, you've read about my home villages... and you've read about a stoic attitude which hasn't changed much in the resulting century. The people there see themselves, or like to think of themselves as "hard ", to a degree which is almost obsessive really... coming perhaps from the Mining background of hard manual labour, perhaps from an "oop norf, not a soovern pooftah" mentality, but for what ever reason you can imagine, it was there; and there even amongst the criminal fraternity. If you couldn't punch your way out of trouble, you weren't worth spit... and that went for anyone who relied upon knives, let alone guns. If you had a reputation for pulling one, you were feared sure, but never respected... only "fookin' pussies" or "bloody psychos" needed things to make them 'ard.
A personal experience of that came when I once got mugged at knife (and screwdriver blade) point once back there, but the people who did it were hated even by the drug dealers, so they were quickly dobbed on by everyone on the sink estate they were from, and taken off the streets... unlike the dealers themselves, who no one would turn in as that was the only joy you got in a small village with only abandoned pithead offices to play in. That's just the way it was. You could be dumb, violent, criminal yes... but there was a twisted sort of honour. Yes, there were guns floating around in Nottingham sure... but an extremely strong counter culture kept it in check, even during the hard times.
And secondly, there's the National zeitgeist. Some of that is the wider "British Stiff Upper Lip" perhaps; Most of us of a certain generation will have some stories of experiencing terrorism, so I won't bore you with mine. Those living in London will have them even now, because it still tends to target for maximum impact... my ex was on the train behind one of ones destroyed in July, and a former closest-friend felt the shockwave from another pass through the Liverpool Street station. But all the same, we deny terrorists the terror they hope to inspire, and life goes on. And of course, many years before, whilst Hitler was raining incendiary death upon our cities... and we "never surrendered", we just made up risqué songs about how many testicles he had instead.
And we just aren't that worried, or impressed with guns anyway. I actually grew up around them; my Uncle was a Gamekeeper on some of the remains of Sherwood Forest... but he only ever showed them us when he was at work in the woods; Otherwise it was locked away in the cupboard. There was never any "getting drunk and showing us what a big man with a big gun" he was. Part of that was the Notts 'Ardness again too (hence he WOULD talk about all the mantraps he claimed to set, which showed his cunning and prowess over those poaching sorts) but it's just not British (any more) to wave weapons around and generally be crude and beastly like that (of course, when we had the maxim gun, and you did not... but now any oik can get one, it rather loses it sheen, what?)
And once you remove the guns, you remove a lot of the stress too, because violence isn't likely to be so suddenly, personally there; I remember once, waiting in Heathrow Terminal 3 Arrivals, clutching my rucksack with clothing packed for a week of passion in London I was about to have (I hope!) with a woman from the internet I was meeting for the first time... hugging it really close to my chest out of nerves... and then looking up and realising two armed officers with sub-machine guns were staring straight at me. "They are watching for a rucksack bomb" was my first thought. Now with hindsight, I'm not suspiciously-Brazilian enough so I'd been able to get away with this; I just smiled back to the officers, and opened up the rucksack, and took out a book to read... Add guns into the equation though, and you give the officer the added "is he going to draw on me?" worries. And give me the worry that this is what they are thinking, and I'm about to be shot to death. What to do... what do I do?! And what about that guy sat facing me? Does he think I'm about to draw? What if he's packing too, and starts a firefight with the guy behind me who doesn't know where the shot came from...?
But without the tension of increased and easily accessible lethality, I was able to effectively de-escalate the tension. I know you can get into all kinds of arguments about where the utility line for risk versus practical existence is... but for we Brits, guns are way, waaaay over the line for what we need to get along with each other. And whilst I'm not a huge fan of the Police (remembering all the overtime they took to break the heads of my family and those around me protesting what in the end was a deliberate political push to destroy their industries) it's full credit to them that, even when faced with a killer who'd shot and threatened to shoot more of their colleagues, even then Mr Moat didn't get his "suicide by cop" ... Yup, there's been occasions, like the afore mentioned sudden Brazilian waxing (sorry) but on the whole, even our armed officers aren't that on edge usually. And for that we all say... Thank heavens for that.