Admissibility of Evidence and “General Unfairness Discretions” in Police v Dunstall [2015] HCA 26

The High Court has unanimously allowed an appeal from South Australian Supreme Court in Police v Dunstall  [2015] HCA 26.  The case considered the discretionary powers of courts to exclude evidence where the admission of the evidence would render the trial unfair. 

Facts of the Case

Mr Dunstall was stopped by the police while driving  in Adelaide, and returned an initial positive breath test.  He was then taken to a police station for a further test, where his breath analysis reading was 0.155 grams of alcohol per 100 millilitres of blood.

Mr Dunstall was charged with the offence of “driving a motor vehicle with the prescribed concentration of alcohol in the driver’s blood” under section 47B(1)(a) of the Road Traffic Act 1961 (SA). 

Under the Act, there is a presumption that in the absence of proof to the contrary, the concentration of alcohol indicated as being present in the defendant’s blood by a breath analysing instrument accurately represents the concentration of alcohol present in the blood of the defendant at the time of analysis, and that this concentration was present in the defendant’s blood at the time of driving (as long as the breath analysis is performed within two hours).  This presumption applies as long as the breath analysing instrument is operated by a person authorised to do so and if specified requirements and procedures are complied with. 

The presumption may be rebutted if the defendant arranges for their blood to be taken by a separate medical practitioner using an approved blood test kit.  Procedures for taking the sample are prescribed by regulation.

Mr Dunstall requested the blood test kit and was taken to the Noarlunga Hospital, where he gave a blood sample.  However, attempts to analyse the sample were unsuccessful.  Evidence was given at trial which suggested that it was probably because the size of the sample was too small.

Case History

Mr Dunstall pleaded not guilty to the offence in the Magistrates Court of South Australia.  Over his objection, certificates of the breath analysis reading and certificates stating that the necessary requirements and procedures had been followed were tendered in court.  The magistrate dismissed the charge referring to the “general unfairness discretion”, as he considered that Mr Dunstall had been deprived of his ability to rebut the presumption through no fault of his own.  The magistrate’s decision essentially excluded the police’s certification evidence.

The police appealed to the Supreme Court, who dismissed the appeal, concurring with the magistrate’s decision. 

The police then appealed to the Full Court of the Supreme Court of South Australia, They also dismissed the appeal on a 2-1 majority.

Decision of the High Court

The police were granted special leave to appeal in the High Court, and the appeal was allowed unanimously (with Nettle J writing a separate opinion but concurring in the result).

The majority of the High Court considered a number of discretion cases established at common law, including R v Lobban (2000) 77 SASR 24, which the magistrate cited in his initial decision.  However, while accepting that discretions may exist in some cases, they did not believe that they should apply in the circumstances of this case:

They also noted that Parliament had designed the legislation specifically to “closely confine the circumstances in which rebuttal evidence may be adduced”, and that:

The High Court ordered the appeal be allowed and remitted to the Magistrates Court for further hearing.

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Police v Dunstall [2015] HCA 26 (5 August 2015) & judgment summary