There are a whole raft of tales here about burglars breaking into a house and being savaged by a pet or hit by the house owner and either suing the house owner or the the police arresting them. The view of most ordinary people here is that a burglar leaves their rights outside the house when they burgle it. The police and courts don't take that view. And don't ever defend yourself against a mugger, and never, ever help someone who is being mugged. The police will arrest you faster than you can say "aren't you going after the mugger?". You are easier to arrest and prosecute. The mugger will be difficult. Or am I just being cynical as well? And all because the definition of "reasonable" is not strictly defined in law.