The UK numbers have almost nothing to do with guns (they didn't have much of a homicide problem even before they cracked down on guns, and used to have a fanastically high murder rate with knives when King James was on the throne), but they did see a rise when UK teens got into US gang style coolness. Tiny changes in young male behavior completely dominate murder rates, because that demographic in the US is 20 to 300 homicides per 100,000, rates you can hit without any guns at all if teens decide that knife fighting is cool and manly, as Italians did up through the early 20th century.
Overwhelmingly the problem. What's the gender divide on murders?
Women don't shoot, they poison.