A person may use such force as is reasonable in the circumstances for the purposes of:
- self-defence; or
- defence of another; or
- defence of property; or
- prevention of crime; or
- lawful arrest.
In assessing the reasonableness of the force used, prosecutors should ask two questions:
- was the use of force necessary in the circumstances, i.e. was there a need for any force at all? And;
- was the force used reasonable in the circumstances?
The courts have indicated that both questions are to answered on the basis of the facts as the accused honestly believed them to be (R v Williams (G) 78 Cr. App R 276), (R v Oatbridge, 94 Cr App R 367) and (Archbold 19-49).
To that extent it is a subjective test. There is, however, an objective element to the test. The jury must then go on to ask themselves whether, on the basis of the facts as the accused believed them to be, a reasonable person would regard the force used as reasonable or excessive.
It is important to bear in mind when assessing whether the force used was reasonable the words of Lord Morris in Palmer v R, 1971 A.C. 814;
If there has been an attack so that self defence is reasonably necessary, it will be recognised that a person defending himself cannot weigh to a nicety the exact measure of his defensive action. If the jury thought that that in a moment of unexpected anguish a person attacked had only done what he honestly and instinctively thought necessary, that would be the most potent evidence that only reasonable defensive action had been taken…
The fact that an act was considered necessary does not mean that the resulting action was reasonable (R v Clegg 1995 1 A.C. 482 HL) and (Archbold 19-41).
However, where it is alleged that a person acted to defend himself/herself from violence, the extent to which the action taken was necessary will, of course, be integral to the reasonableness of the force used.
In R v O’Grady 85 Cr App R 315 it was held by the Court of Appeal that a defendant was not entitled to rely, so far as self-defence is concerned, upon a mistake of fact which had been induced by voluntary intoxication.
There is no rule in law to say that a person must wait to be struck first before they may defend themselves: R v Deana, 2 Cr.App.R. 75.
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. 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.
Article extracted from http://www.cps.gov.uk/legal/s_to_u/self_defence/