Even if guns were illegal(wich would be shit too, given a honest person would not be able to get a gun to defend against the dishonest), people would still be easily able to get guns.
Here is where I usually go "Gun control [to the extent of that the UK has] could never be implemented [in the US]", or something similar. Because the US has so many guns that if they were made illegal that even with all the honest handings-in/deactivations/destroyings of weaponry, there'd be enough left in the general population[1] to make it unsafe for those that unilaterally disarmed. (And, in theory, also more unsafe for those that were never armed
but could have been.)
In the UK, though, there
are gun crimes, and there
are illegal guns... Probably more so, since a string of pretty much one-off events[2] made legitimate gun-ownership almost non-existent. But the general populace are not armed. Petty robbers are therefore never armed, and most people[3] never encounter a firearm. This feeds into the police not needing to be generally armed (although there are armed-response units available, when required), which may well feed back into the habits of the criminals, and back on to the general populace, etc...
There's one part of the UK where there's significant (homocidal) fire-arm death rate, according to figures I have here... Northern Ireland has a homicide rate of 5.24 deaths per 100,000 people, per year. Larger than the US's figure of 4.14, but both of these
much larger than the England/Wales rate of 0.07 and the Scottish rate of 0.19.
Suicide (by fire-arm) rates for NI is 1.34, c.f. US's 5.71 and across mainland Britain it's 0.33. To add to this, there's 0.12 "Unintentional" deaths sit approximately half way between the US (0.23) and the mainland (0.01 to 0.02).
Note, the results for the US are from a different source and different years from the UK ones. And, actually, NI/Scottish results are back before a lot of the Irish 'Troubles' were politically resolved... So that may be skewing things. (I checked, and there's no results for Eire (non-British Ireland) in the source I'm looking at.)
Given this note, I'm
not going to say as how we're generally Ok without guns (having no general history of having them) with supporting evidence that the bit of the UK where there was a vested interest in certain 'active' individuals having guns, because the people (and/or authorities) who opposed them were almost certainly going to be just as armed... But you've got to admit that it'd be a good supporting argument to having a place where guns are not, and
have never really been, so commonplace.
Some might be surprised that with a much higher amount of gun ownership that the US only has twenty times or so the accidental deaths of mainland Britain. On the contrary, I expect that in a place where guns are commonplace, the everyday usage of the weapons would lend themselves to having a much more open attitude to teaching about their general safety, both by the owners and those around them. (The laws of the UK, definitely arguable about being draconian in many respects, are quite strict about weapon ownership and where they are stored, but when you're not handling a gun every other day, or so, you're probably more prone to
certain accidents.)
The fire-arm suicide rate is much higher in the US, and really bulks the US's
total fire-arms death-rate up, and position in the rankings. I suppose I should check the general national suicide-rates before I comment on this, though. I suspect that when someone is desperate enough to go down this route, having a gun at hand means that you're already provided with one of the more obvious solutions.
[1] Either already illegally being circulated, or from those previously legal owners that went "whooops, just had my entire collection destroyed in a freak meteorite impact!"/whatever, totally 'unaware' that some kind and prescient person had managed to remove his collection and thus save it from destruction.
[2] Hard cases making bad laws, it could be argued.
[3] There are possible exceptions to this in some inner-city 'gangs', which (if you care to peruse through various news reports) seems to be making gang-on-gang killings and collateral deaths a large proportion of the killings. Much more than the occasional "going postal" event, or other criminal revenge-inspired rampage. American influences are found aplenty, in these sub-cultures, but I don't know how one would quantify the importation of the willingness to use guns in the same memetic package as the rest the attitude arrives in...