Wednesday, 23 September 2015

The High Court puts SA breath test laws to the fairness test

Under South Australian drink-driving laws, if you blow a positive breath test you can go to a doctor of your choice and get a blood test to confirm its correctness. But what happens if the doctor makes a mistake and the blood test can't be used? In a case that made it all the way to the High Court, that's exactly what happened, provoking an interesting debate over judges' discretion to ensure a fair trial.

In SA Police v Dunstall [2015] HCA 26, the High Court rejected an argument that courts can exclude evidence for broad-textured reasons of 'fairness', where to do so would be contrary to the intent of Parliament in a particular legislative scheme.

How did it get to the High Court?

Mr Dunstall had successfully argued for a Magistrate to exclude evidence of his positive breath test taken by police on the basis of 'general unfairness'. While he had taken the opportunity to challenge his drink-driving charge by obtaining a blood test in the manner provided for under SA law, the medical practitioner who performed the test failed to take enough blood so the sample couldn't be analysed, and it couldn't be used to challenge or confirm the blood alcohol reading on his positive breath test.  Of course, once the breath test evidence had been excluded, there was insufficient evidence to sustain a drink-driving conviction.

SA Police appealed the Magistrate's decision, and lost, in the SA Supreme Court and Full Court.  The appeal then went to the High Court, which found in favour of SA Police.

The 'fairness discretion' and the question before the High Court

It was no surprise that the Court confirmed the existence of a 'fairness discretion': a trial judge has certain discretionary powers to ensure that an accused receives a fair trial according to law, including by excluding evidence or, in rare cases, by ordering a stay of proceedings.

A trial judge can exclude evidence in three well recognised categories of discretion:

  • The Christie discretion allows a judge to exclude evidence where its probative value is outweighed by the risk of prejudice to the accused person.  
  • The Bunning v Cross discretion enables a judge to exclude evidence that has been tainted by illegality or impropriety.  
  • The Lee discretion enables the exclusion of confessional statements where certain rules about how confessions can be obtained have been breached.

None of these 'discretions' were available in the case of Mr Dunstall's blood test, which was best characterised as a 'loss of evidence' through no fault of either party.  The High Court had to decide whether a judge has power to exclude probative evidence simply on the basis that its admission could be unfair to the accused.

The High Court's decision

The Court found that Mr Dunstall's argument failed to come to terms with the legislative scheme.  Under the SA law, the offence of drink-driving was established by proof of the breath analysis reading alone.  Blood test evidence could be used to confirm, or to call into question, the breath test evidence, but a defendant does not have a statutory 'right' to blood test evidence to rebut the presumption that the breath test was reliable.  The onus is wholly on the defendant to procure the 'second opinion' evidence.  Where the defendant tries to obtain blood test evidence and, through no fault of their own or that of the Police, these efforts fail, it is clearly intended by the SA legislation that the evidence of the individual's blood alcohol level provided by the breath test cannot be challenged.  The only circumstances in which the breath test could be challenged where a faulty blood test was taken were those explicitly provided for in the legislation, ie where a faulty test kit was provided to the accused by Police.  Accordingly, in this case it was not open for a court to decide to exclude the breath test evidence.

In a separate concurring opinion, Justice Nettle considered the scope of a potential fairness discretion, finding that a 'residual discretion' exists to permit a judge to exclude otherwise admissible evidence to prevent an 'unacceptable risk of miscarriage of justice'.  However, Nettle J found that Mr Dunstall could not show an unacceptable risk of injustice, but only that the loss of his blood test evidence 'might have' have had such a result.  In Nettle J's words, the fairness discretion does not exist:
to give effect to idiosyncratic notions of "fair play" or "whether the forensic contest is an even one", still less to deny effect to statutory  modifications of common law means of proof which, because of idiosyncratic notions of what is fair, a judge may disapprove.
In short, the 'unfairness' in Mr Dunstall's case resulted from the proper operation of the legislative scheme itself.  Whatever the scope of a court's 'fairness discretion' to prevent injustice in a criminal proceeding, it cannot override the clear intent of Parliament.

Victorian Government clients seeking advice on public law can contact:

Rachel Amamoo
Managing Principal Solicitor
03 8684 0899

Jordina Rust
Solicitor
03 8684 0468

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