The move to dilute the right to silence in NSW is unjust, constitutionally questionable and unnecessary.

The O'Farrell government announced a “watering down” of right to silence laws in response to bikie gang violence. Amendments to the Evidence Act will be introduced to allow juries to draw adverse inferences from those who produce evidence at trial after refusing to answer questions from police.

The principle that no person is obliged to incriminate themself is an indispensable element of the panoply of safeguards that secure the citizen’s personal liberty against state oppression. The criminal justice system in common law countries excludes involuntary confessions, bans torture, upholds the presumption of innocence, requires proof of criminal charges beyond reasonable doubt and excludes irrelevant and unreliable evidence. The right to remain silent is part of this system that was established in the seventeenth century revolt against the practices of the Star Chamber and the High Commission.

It is part of the general common law freedom that no person be compelled on pain of punishment to answer any question asked by another person.

This is an aspect of the person’s right to privacy, without which individual liberty is unrealisable. Imagine a life where all your plans, whether personal, emotional or commercial, are available to all on demand. Criminal justice is unattainable without the cooperation of truthful witnesses. However, the common law has historically recognised certain specific immunities.

No person is bound to give answers to questions that may incriminate them. A suspect under investigation has no duty to answer questions of any kind. A person under trial for a criminal offence cannot be compelled to give evidence, and no adverse inference can be drawn from silence.

A person who is investigated as a suspect receives the traditional caution: “You do not have to say anything if you do not wish to do so, but anything you do say may be used against you in a court of law”.

If the proposed bill is enacted, the caution will be something like: “You do not have to say anything. But it may harm your defence if you do not mention when questioned something which you later rely on in court. Anything you do say may be given in evidence”.

This is similar to the change made in England by the Criminal Justice and Public Order Act 1994. Supporters of this change say that innocent people do not resort to silence, only the guilty do. This is precisely the kind of reason that the Star Chamber gave when they tortured recalcitrant prisoners. If you are innocent, why are you not answering my questions?

Supporters also say that organised crime gangs are able to erect walls of silence that the police cannot penetrate. It is true that gang members are often sworn to silence by loyalty or fear of retribution. But this has always been the case in relation to criminal organisations, whether they are the Mafia, Jihadists or the Medellin drug cartel. Law enforcement is tougher against organised crime but it only means that the law enforcers have to work harder and smarter. Liberty is not cheaply secured.

The proposed change is dangerous for other reasons. The rule change is not likely to frighten hardened criminals or criminal gangs, but it will intimidate the innocent. An innocent person may not answer a question for any number of reasons such as mental capacity, intoxication, age, stress, loss of recall, professional advice, misunderstanding of the question, ignorance of rights and duties, and fear of consequences.

A judge will have responsibility to direct the jury on whether the silence was reasonable in the relevant circumstances and on the appropriate inferences to be drawn from the silence. Thus a simple rule is replaced by a complex one making the law more uncertain in its application to the individual case thereby defeating a central element of the rule of law.

It may also be questioned whether the proposed change strikes at the heart of the requirements of a fair trial. A procedure that compromises the fairness of criminal trials may be seen to affect the institutional integrity of the NSW courts which are part of the system of courts exercising federal judicial power.

If so, there is at least a slight chance that the High Court may find the proposed change inconsistent with the requirements of Chapter III of the Constitution. This though is not the most important consideration. The proposed law may pass the test of constitutional law but surely fails the test of constitutional principle.

It should be opposed principally as a form of compulsion that diminishes personal liberty by weakening the key safeguards of the presumption of innocence and the burden of the prosecution to prove criminal charges beyond a reasonable doubt.