Speaking from experience from living in a country that has tight gun control, yes the hardened criminals have illegal guns, but as the general populace is (generally) unarmed the petty or opportunist criminal is also unarmed. Our police force is also generally unarmed (they do not carry sidearms, but usually have handguns and shot guns secured in a lock box in their squad cars, and in each major centre has a special squad to be called out when there is an armed offender - sort of like a SWAT team) and so the criminals do not feel the need to be heavily armed. I'm not saying gun crime does not happen or that there have not been times police officers should have been armed, but I believe the system generally works, just as, I am sure, there are situations in the USA where armed citizens are still not able to defend themselves.

I am also not saying that what works here would work elsewhere. Mrkim gave the example of Chicago and NYC having tight gun control laws that are ineffective. I'd suggest that is because there is no effective border between the area with the stricter laws and those areas without. There are some advantages to living in an island nation. I like our system the way it is and wouldn't like to see the gun laws relaxed, but I do not think it would be possible to achieve the same situation in other countries, especially the USA given the feelings of it's citizens.