lol at the upgrade from burgling your house to raping you mum!
Anyway in the situation above you would be allowed to use reasonable force to stop the intruder, that reasonable force may result in their death (It would not necessarily be unreasonable to hit them once or twice with a cricket bat) and then if deemed necessary a jury of 12 of your peers will decide if your actions were reasonable.
If however you break up the act and then kill the attacker deliberately (ie carrying on hitting them with a cricket bat until their brains are all on the outside) once they no long pose a threat to you or your mum then you will be charged with manslaughter and once again tried in front of a jury of your peers to decide if what you did was reasonable.
Those who can't see the difference between acting in self defence and being judge, jury and executioner are the people with an issue in this thread. This is how our justice system works and generally speaking it works pretty well.