Self-Defence and Prevention of Crime
Under the common law, a person can use reasonable force to defend him/herself, another person or property. Section 3 of the Criminal Law Act 1967 allows a person to use reasonable force in the prevention of crime or making an arrest. Self-defence is a complete defence, leading to an acquittal.
Reasonable Force
In assessing whether a defendant had used only reasonable force, Lord Morris in Palmer felt that a jury should be directed to look at the particular facts and circumstances of the case.
If a person is not acting in self-defence or uses excessive force, the defence will fail as in:
- Clegg, where a soldier's fourth bullet went through the rear screen of a car that did not stop at an army checkpoint. Note that a retrial was ordered in the Clegg case, based on new forensic evidence. Read a BBC News article about the case.
- Martin, who shot two burglars in the back. See the BBC News article: Tony Martin: Crime and Controversy.
If the defendant makes a mistake about the amount of force that should have been used then, according to cases such as Scarlett and Owino, the jury must decide whether the force used was reasonable in the circumstances as he believed them to be.
Useful BBC News articles: Is assault lawful when protecting someone? and BBC News Q&A: What is reasonable force?
Pre-emptive Attacks
It is not absolutely necessary that the defendant be attacked first. As Lord Griffith said in Beckford: “A man about to be attacked does not have to wait for his assailant to strike the first blow or fire the first shot; circumstances may justify a pre-emptive strike.”
If a person believes that he may be attacked, he may arm himself for his own protection. See: Attorney-General’s Reference (No 2 of 1983). However, such a defendant may commit other offences, eg, the unlawful possession of a fire-arm.
Mistake as to Self-defence
If a defendant mistakenly believes himself to be threatened or mistakenly believes that an offence is being committed by another person, s/he will be judged on the facts as they honestly believed them to be, and allowed to use a reasonable degree of force. The following defendants had their convictions quashed in such circumstances: Williams (Gladstone), Beckford and Faraj.
Intoxication and Self-defence
It has been held that a drunken mistake as to self-defence, however genuinely believed, is no defence to a criminal charge: O’Grady.