We would never advise that confronting a burglar is the best course of action. While we may be lucky in the UK in that we can assume that the burglar doesn’t have a gun, (the reverse being true in the USA), we also don’t know what that individual is capable of. Burglars know they may need to defend themselves and will normally carry some kind of weapon, or have had training they can use to defend themselves. In most cases, it is best not to engage with the burglar and not even let them know you are aware of their presence (if they break in during the night assuming everyone is asleep). Burglars are interested in relieving you of your valuables, not taking your life, although there is no telling what they might do when cornered. It is always best not to put yourself in danger.
With this in mind, we know that some people with police training, martial arts experience or other physical capacity to defend themselves against attack may decide to take on a home invader, so it’s important to know where the law stands on this matter, and what is defined as “reasonable force”. The 2013 Crime and Courts Act gave some clarity to the matter, and ruled that homeowners could use disproportionate and reasonable force to defend themselves against attack in their own home, as long as it was not “grossly disproportionate”.
Personal definitions may vary here, but generally speaking you would be within your rights to attack an intruder if they were actively threatening you. However, creeping up behind them and striking them on the back of the head could be construed as disproportionate, as your life was not actually in danger in that moment of striking them. Courts would take an individual view on this if there were mitigating circumstances, (for example, a single woman living along taking this action against a male twice her size), but generally speaking, attacking from behind would be disproportionate.
If the intruder is in the process of approaching you and you believe they will attack, then you can strike first as you reasonably believe your life is in danger. To continue to attack after the intruder is on the floor, or otherwise detained, would be against the law as you have neutralised the threat and they cannot cause any harm to you if they are unconscious or restrained.
In terms of weapons, it would best not to grab a knife as all you would be doing is introducing a bladed weapon into the situation which could then be used against you. A blunt, heavy object is a little safer but do remember that any weapon you grab can be taken from you and used against you – exercise caution here.
If the burglar flees, you are within your right to give chase and restrain them if you are able. You can legally use reasonable force to retrieve your property and to restrain the criminal; you can even perform a citizen’s arrest.
Our recommended course of action is to call the police, and do not confront or engage with a burglar. However, if you are confident you will not come to any harm (if you’re a kickboxing champion, for example) then you may decide that on balance, you could attempt to stop the crime and restrain the burglar. It is hard, though, to act rationally and reasonably in the heat of the moment, so this should always be a last resort and only if you fear for you safety.