Where anyone can get a gun? If you live in the middle of nowhere, lots of people around you will have guns (though they could be dozens of miles away in the best case), and obviously where there are more people the police can get guns, or call up the military if they can't for some reason (what country is that though?)
An authorised firearms officer (AFO) is a British police officer who is authorised, and has been trained, to carry and use firearms. The designation is significant because in the United Kingdom most police officers do not routinely carry firearms, although they can be equipped with tasers.
In 2019/20 fiscal year, there were 19,372 police operations throughout England and Wales in which the deployment of firearms was authorised and 6,518 firearms officers, 4.9% of the 132,467 active FTE officers. Following the November 2015 Paris attacks it was decided to significantly increase the numbers of armed officers, particularly in London.