Onus of Proof

What is Onus of Proof?

The general principle in the Queensland Criminal Justice System (and throughout Australia) is that a person cannot be held criminally responsible unless the prosecution proves its case to the high standard of “beyond a reasonable doubt”. It is therefore not enough for the prosecution to prove that it is highly likely the accused committed the offence in question. There needs to be no reasonable doubt in the mind of the Jury (or other final decision-maker) that the person did what they have been accused of.

This principle is extremely important as it allows for the protection of innocent persons from being wrongly convicted of crimes.

The term “onus of proof” refers to this obligation of the prosecution to prove the case against the accused and it is a term that is often used in courts, particularly in criminal trials.

In some cases, however, the onus shifts from the prosecution to the defence which means that it is up to the defendant to prove certain things.

There are generally considered to be two different forms of the onus:

  1. The persuasive onus (also called the legal burden); and
  2. The evidential onus (also called the evidential burden).

We will go through each of these in turn.

What is the Persuasive Onus?

As briefly discussed above, the prosecution have the persuasive onus or the legal burden of proving that a person committed the offence that they have been charged with. This simply means that it is up to the prosecution to persuade a Jury that the offence has been committed.

If the prosecution cannot prove their case beyond reasonable doubt (often referred to as the “criminal standard of proof”), the accused person should be found not guilty.

What is the Evidential Onus

As a general rule, a defendant is not required to prove or disprove anything and, in most cases, this right extends from initial contact with police through to the trial.

However if a defendant wants to raise a defence, they may have an evidential onus which requires them to point to or produce evidence which might suggest that they do in fact have a defence.

The wording of the charge itself will normally indicate whether the defendant has an evidential onus. Some examples include:

  • “… unless the contrary is proved”;
  • “… in the absence of proof to the contrary”;
  • “… if the person proves”; or
  • “… unless evidence is given to the contrary”.

The evidential onus is therefore not strictly an “onus of proof” as it is not necessary for the defendant to prove they have a defence. They simply need to be able to raise the possibility of a defence and be able to refer to some form of evidence to be able to support their defence claim.

For example, if a person has been charged with the offence of “carnal knowledge with children under 16”, they may raise a defence that they believed on reasonable grounds that the person was in fact 16 years or older at the time of the alleged offence.

To be able to raise such a defence, the defendant must be able to refer to evidence which supports their claim that they believed the child was 16 or older. This is their evidential onus.

It is important to note that, unlike the persuasive onus which must be satisfied beyond a reasonable doubt, the defendant has a much lower threshold to meet. The standard of proof for the evidential onus is “on the balance of probabilities”. In other words, the probability of the defence being true must just be greater than it being false – it does not need to be beyond all reasonable doubt.

If a defendant is able to satisfy their evidential onus, it is then up to the prosecution to negate (or disprove) the defence beyond a reasonable doubt. This means that that the prosecution must be able to show that there is not only enough evidence to prove their accusations against the defendant but also to prove that the Jury should have no doubt that the defence cannot be relied upon by the accused.