Please be careful. A bloke with a knife needs less than a second to slice your stomach open

Good point, but it also depends on how good you are with a gun. Anyone in their right mind that owns a handgun should know how to use it, and practice with it at a local firing range. Plus, pulling the trigger on someone is a huge decision, but if someone is lunging at you with a knife, the decision should not take long because that is a threat against your own life.