Are you allowed to defend yourself and if you do what are the legal consequences in case you hurt the intruder?
According the The Crown Prosecution Service (CPS) you are not expected to wait till you get attacked to start using offensive force.
Any home owner can use a reasonable force to protect themselves an even can carry citizen arrest.
If you acted in self-defense and the intruder dies, you will still have acted lawfully.
A rugby tackle or a single blow would be considered as a reasonable force.
If you act over the top and in a calculated revenge the law won't protect you.