I posted this on survivalistboards, I'll repost it here.
http://www.bbc.co.uk/news/uk-19886504
My favourite:
How likely is prosecution?
There have been very few prosecutions in these circumstances. Between 1990 and 2005 there were 11 prosecutions of people who attacked intruders. Seven of them related to domestic burglaries.
One of the cases that was prosecuted involved a man who lay in wait for an intruder and then beat him, threw him into a pit and set him alight.
Some cases and news articles: There is at least one fire arms incident from what I remember.
http://www.dailymail.co.uk/news/arti...l-burglar.html
http://protectyourself.cc/homeowner-...-self-defence/
http://news.bbc.co.uk/1/hi/england/d...re/3954033.stm
http://www.dailymail.co.uk/news/arti...-intruder.html
http://news.bbc.co.uk/1/hi/england/2550627.stm
http://www.telegraph.co.uk/news/ukne...aid-death.html
http://www.guardian.co.uk/uk/2010/ap...charge-dropped
http://www.dailymail.co.uk/news/arti...f-defence.html
http://www.bbc.co.uk/news/uk-england...shire-19496531
http://www.dailymail.co.uk/news/arti...ence-post.html
Pre-emptive attack as defense:
http://www.cps.gov.uk/legal/s_to_u/s...e/#Pre-emptive
Pre-emptive strikes
There is no rule in law to say that a person must wait to be struck first before they may defend themselves, (see R v Deana, 2 Cr App R 75).
Duty to retreat:
http://www.cps.gov.uk/legal/s_to_u/s...ce/#Retreating
Retreating
Failure to retreat when attacked and when it is possible and safe to do so, is not conclusive evidence that a person was not acting in self defence. It is simply a factor to be taken into account rather than as giving rise to a duty to retreat when deciding whether the degree of force was reasonable in the circumstances (section 76(6) Criminal Justice and Immigration Act 2008). It is not necessary that the defendant demonstrates by walking away that he does not want to engage in physical violence: (R v Bird 81 Cr App R 110).
If you put your hands out in front of you (palms outwards), take one step back and say STOP, you have fulfilled your "duty to retreat". Then its "Teach him a lesson boys, teach him all the way"
Unless you have the money to burn and the relevant training a Katana makes a poor choice, for 1 it's a long blade to be wielding in confined space, a machete, billhook or khukuri would make a better alternative if you desired to go the bladed tool option. As you say you're a smaller skinny white dude, you can pretty much go to town if you remember,
"you feared for your safety and that of your family you acted instinctively".