Technically, British law isn't that bad.
There is a great misconception that British law doesn't allow a person to defend themselves. I will admit there are cases, as there are in every country, where the law seems to fail the person we perceive to be in the right, but these cases number in the minority and we only know of them because they stand out as an oddity and people yell about injustice etc. However, if you actually look at written law you'll see its perfectly possible to defend yourself up to and including the killing of another person in the act. See below the source direct from the UK's Crown Prosecution Service.
Source -
http://www.cps.gov.uk/legal/s_to_u/self_defence/
tl:dr (loose translation) - if you use force you believe to be necessary at the time of the incident to stop your attacker and to prevent injury to you or others then you are not at fault. If you continue to attack an assailant once he/she is "stopped" then you are no longer defending yourself.
Another area of contention is weapons.
If you pick up an item to defend yourself so long as its not something you've purposefully had waiting to attack someone with then you're fine, in the example op gave us the lad picked up a sword that was a collector piece, was not intended for use against people but in this case to display to the attacker to discourage further attack or whatever (little detail in the report about why the sword was there but anyway he's OK grabbing it in a rush). British law doesn't expect you to know the limits in the heat of the moment. So later you can honestly say, look, I collect swords, one was there, I grabbed it, etc etc etc. You get the picture.
On the other hand, if you purposefully put a sword next your front door with an aim of stabbing intruders, that's intent, this included modified house hold objects for weapons.... think nails and baseball bats. Pre-planned assault. No getting around it.
Anyway this is just my interpretation, and in my opinion be it wrong or not, I think British law is pretty straight forward and fair on the subject of self defence. There are some strange grey areas, such as preemptive attacks but these are pretty much covers by you believe at the time that you or your family/friends are in imminent danger and you fear for your safety you can use enough force to stop someone and leg it!
Do correct me if I'm wrong, Its all education in the end. [emoji4]
you can plan, but plan with intelligence. Plan to stop attackers, don't plan to kill them, if it comes to that or mistakes are made then the law is on your side. Every life is precious, aim to help everyone.
