Most people who return a positive breath test will plead guilty and take steps towards securing the most lenient penalty, often seeking to avoid a criminal conviction and licence disqualification.
Those steps might include getting an experienced lawyer, completing a Traffic Offender Program, obtaining character references and perhaps writing a letter of apology.
But one South Australian man who recorded a high range reading took his case all the way to the High Court, arguing that the breath analysis certificate should not be admitted into evidence as he was denied the opportunity of having a blood analysis result.
Police v Dunstall 
Jason Dunstall was cruising the streets of Adelaide when he was stopped by police for a random breath test. He later underwent a breath analysis which returned a reading of 0.155 grams of alcohol per 100 millilitres of blood – more than three times the legal limit – and was charged with high range PCA (drink driving).
Police informed him of his right to a blood analysis, and he was taken to hospital for the sample to be taken. But due to a medical mishap, the doctor failed to take enough blood for the sample to be analysed. This left the breath analysis result as the only evidence of his blood alcohol reading.
South Australian law says that there is a presumption that the breath analysis reading is indicative of the alcohol present in a driver’s bloodstream, as long as all procedural requirements are met.
Similar provisions exist in New South Wales under section 109 of the Road Transport Act 2013.
However, a person can ‘rebut’ (overturn) that presumption by presenting the results of a blood analysis. Drivers who return a positive breath analysis are allowed to request a blood test. Again, similar provisions exist in New South Wales under Schedule 3 of the Road Transport Act 2013.
Mr Dunstall pleaded not guilty to the charges, arguing that the breath analysis should not be admitted because he elected to have his blood analysed, and the failure of that analysis to come through was no fault of his own.
The Local Court Magistrate accepted Mr Dunstall’s argument, and he was found ‘not guilty’ as a result.
But unfortunately for Mr Dunstall, it didn’t end there: police appealed the case to the Supreme Court, which upheld the Magistrate’s decision – as did the Full Court of the Supreme Court.
However, Mr Dunstall’s luck ran out when the matter reached the High Court, with the majority upholding the appeal in favour of the police.
Chief Justice French, along with Justices Kiefel, Bell, Gageler and Keane said that because there was no statutory right of a defendant to have a blood sample taken, and because there was nothing to suggest the results of the breath analysis were inaccurate, no unfairness was caused to Mr Dunstall in admitting the results.
What About Drug Cases?
The High Court looked at several other cases when handing down its decision in Dunstall.
One of those was the case of R v Lobban; a South Australian case which involved a man charged with drug trafficking after police located 7.2 kilograms of what they presumed was cannabis in his car. They later conducted a search of his home and found several cannabis plants.
Police seized the vegetable matter and sent it off for analysis to determine whether it was in fact cannabis, and to obtain a certificate to that effect. The defendant had the opportunity to conduct his own independent analysis, but was not able to do so because police misplaced the vegetable matter after their analysis had been conducted.
Mr Lobban sought to argue that it would be unfair to admit the certificate into evidence as he was unable to conduct his own tests. But similarly, the High Court found that no unfairness was caused to him.
R v Lobban established that ‘to exclude probative evidence untainted by illegality, impropriety or risk of prejudice where its admission would be unfair to the accused in the sense that it would make the trial of the accused an unfair trial.’