Offences of assault range from the most serious which may be charged as grievous bodily harm with intent or even attempted murder right down to the most minor matter where no injury of any kind whatsoever is caused which may be charged as ‘common assault’. But no matter how serious or otherwise the assaults, all of these offences have one thing in common; they are all subject to the law of self defence. Anybody who is attacked is entitled to defend themselves and anybody who sees another person being attacked is entitled to go to the defence of that other person; however there are two principles that the law applies.
The first is that if it is possible you should seek to remove yourself from the position before engaging in a fight, those who willingly engage in aggressive behaviour and an exchange of blows are unlikely to be able to claim self defence.
The second principle is that reasonable force must be used. By reasonable the law means proportionate. So for example if man A were to be punched by man B then man B may be entitled to return the blow in order to defend himself to return a punch with a punch would be likely to be considered by the court to be reasonable. If man B however were to pull out a gun and shoot man A this would not be considered reasonable force and the defence of self defence would not succeed.
Self defence is one of the most complex and grey areas of criminal cases although the law itself is relatively straight forward the facts which may pertain to any case by its nature will be unique and often open to interpretation as different parties have different recollections and different views. It is always possible for one to defend themselves indeed that must be the case however the law of self defence does not give permission to engage in fights or acts of aggression willy-nilly and even when one is forced to defend oneself only reasonable force can be used. If force going beyond reasonable force is used then an assault may still be committed even though there may be mitigating circumstances.
What constitutes a legitimate defence of self defence depends upon the precise circumstances and facts and each of those will be unique to the case concerned.