People who defend themselves are charged more often than they expect. The police at the scene see two people and an injury, and frequently charge both, or charge whoever is still standing. Being the one who was attacked does not stop you being arrested.

This page is about what happens next. For the provision itself, see our explainer on self-defence under sections 34 and 35.

What does the law require?

Section 34 provides that a person is not guilty of an offence if they believe on reasonable grounds that force or a threat of force is being used against them or another person, the act is committed for the purpose of defending against it, and the act committed is reasonable in the circumstances.

The belief has to be reasonable, not correct. Someone who reasonably but mistakenly believes they are about to be attacked — believing a weapon was being drawn, for instance — can still act in self-defence.

Who has to prove it?

Not you. Once there is an air of reality to the defence, the burden is on the Crown to disprove it beyond a reasonable doubt. This is one of the genuine structural advantages in a criminal trial, and it is why the evidence about what led up to the incident matters as much as the incident itself.

What does a court weigh?

Section 34(2) sets out the factors, and two of them do most of the work in real cases.

  • Whether other means were available and how imminent the force was.
  • The history between the parties — section 34(2)(f) covers the nature, duration and history of the relationship including any prior use or threat of force, and section 34(2)(f.1) covers any history of interaction or communication between them.
  • The nature of the threat, the person's role in the incident, whether weapons were involved, the relative size, age and physical capabilities of the parties, and the proportionality of the response.

That history factor is why a response which looks excessive in isolation can be reasonable in context. A person who knows what the other party has done before is not required to wait and find out again.

When is self-defence not available?

Section 34(3) provides that the defence does not apply where the force was used or threatened by someone doing something they are required or authorised by law to do in the administration or enforcement of the law — unless the person believed on reasonable grounds that the other person was acting unlawfully.

In practice, that means resisting a lawful arrest is not self-defence. Whether the arrest was lawful is a separate question, and one worth asking.

What should you do at the scene and afterwards?

  • Ask for a lawyer and stop talking. "It was self-defence" feels like the obvious thing to say. It is also a statement, it can be used, and it concedes that you did the act — which narrows your options before anyone has seen the disclosure.
  • Get medical attention and make sure your own injuries are documented. Your injuries are evidence.
  • Photograph everything — marks, torn clothing, the scene.
  • Note who was present. Independent witnesses matter more than either party's account.
  • Preserve the history. Prior threatening messages, past incidents and police reports go directly to section 34(2)(f) and (f.1), and they disappear quickly if nobody saves them.
  • Do not contact the other party. If you have been released on conditions, that is a separate offence.

Is claiming self-defence a strategic decision?

Yes, and it should be made with the disclosure in front of you rather than at the roadside. Advancing self-defence generally means accepting that the act occurred, which closes off arguments about identity or whether anything happened at all.

That is often the right trade, because a successful self-defence claim is a complete answer to the charge rather than a mitigating factor. But it is a choice, and it is not one to make while being questioned.

If you have been charged after defending yourself, see our page on assault charges, or on domestic violence charges where the allegation arises between partners.