Case Details
- Citation: [2023] SGHC 179
- Title: Tham Saik Mun Simon v Public Prosecutor
- Court: High Court of the Republic of Singapore (General Division)
- Case Number: Magistrate’s Appeal No 9163 of 2022
- Date of Decision: 27 June 2023
- Judge: Vincent Hoong J
- Appellant: Tham Saik Mun Simon
- Respondent: Public Prosecutor
- Procedural Posture: Appeal against conviction and sentence from the District Court (drink-driving offence under the Road Traffic Act)
- Legal Areas: Criminal Law — Statutory offences; Criminal Procedure and Sentencing — Sentencing (including appeals)
- Statutes Referenced: Criminal Procedure Code; Road Traffic Act
- Key Statutory Provisions: Road Traffic Act ss 67(1)(b), 71A(1) and 71A(2)(b)(ii)
- Judgment Length: 54 pages; 14,811 words
- Authorities Cited (as per metadata): [2023] SGDC 15; [2023] SGHC 179
Summary
In Tham Saik Mun Simon v Public Prosecutor [2023] SGHC 179, the High Court dismissed a drink-driving appeal brought by the accused, Mr Tham Saik Mun Simon, who was convicted in the District Court of driving with a breath alcohol concentration above the prescribed limit. The central issue was not whether the accused was driving, but whether he could rebut the statutory presumption in s 71A(1) of the Road Traffic Act (“RTA”) by relying on the exception in s 71A(2). Specifically, he argued that his elevated breath alcohol readings were caused by his post-driving oral application of Bonjela gel, which he said he used to alleviate pain from ulcers and toothache.
The High Court accepted that the accused had applied Bonjela gel after he had ceased driving, thereby satisfying the first element of the s 71A(2) exception. However, the court held that the accused failed to prove, on a balance of probabilities, the second element: that but for the post-driving application of Bonjela gel, his breath alcohol level would not have exceeded the prescribed limit. The court’s reasoning turned on the evidential reliability of the breath evidential analyser (BEA) readings, the scientific evidence concerning whether Bonjela gel could cause “mouth alcohol” to be detected as “breath alcohol” by the Dräger Alcotest 9510 SG machine, and the procedural integrity of the breathalyser testing process.
What Were the Facts of This Case?
The accused drove a motor van at about 2.00am on 14 June 2019 at an open-air carpark near Block 146 Yishun Street 11. A complainant reported to the police that a “drunk driver” wanted to hit him at the location. Police officers attended and subjected the accused to an initial breathalyser test at the incident location. The accused failed that test, was arrested for drink-driving, and was escorted to Woodlands Police Division Headquarters for further investigations.
At Woodlands Police Division HQ, a breathalyser test was administered at about 4.04am. The breath evidential analyser (BEA) produced a result showing a breath alcohol concentration of 75 microgrammes (µg) of alcohol per 100 millilitres (ml) of breath. This exceeded the prescribed limit of 35µg/100ml under the RTA framework for drink-driving offences. The accused was therefore charged with an offence under s 67(1)(b) of the RTA, which criminalises driving with a body alcohol content above the prescribed limit.
At trial, the accused claimed trial and advanced a defence that his breath alcohol readings were attributable to his post-driving oral application of Bonjela gel. He maintained that after he had parked the vehicle, he applied Bonjela gel to his mouth to relieve pain from ulcers and toothache. He also asserted that he had consumed less than one jug of beer prior to driving. The defence did not dispute that the BEA reading was 75µg/100ml; rather, it sought to explain why that reading should not be treated as reflecting his alcohol level at the time of driving.
The prosecution adduced evidence from multiple witnesses, including the arresting officer, the administering officer, and expert witnesses. In particular, the Health Sciences Authority (HSA) expert gave evidence on the effects of oral application of Bonjela gel on breath alcohol levels. The prosecution also relied on Dräger-related expert evidence concerning the functionality of the Dräger Alcotest 9510 SG machine and whether it can distinguish “mouth alcohol” from “breath alcohol”. A Draeger experimenter testified about experiments conducted to assess the effect of Bonjela gel on results obtained by the machine. The accused called his own defence expert who conducted an experiment on the effects of Bonjela gel on BEA test results and prepared supporting study materials.
What Were the Key Legal Issues?
The appeal required the High Court to determine whether the accused could rebut the statutory presumption under s 71A(1) of the RTA. Under s 71A(1), the court assumes that the accused’s alcohol level at the time of the offence was the same as that reflected in the breath sample. This assumption is rebuttable only by the exception in s 71A(2), where the accused bears the burden of proving the exception on a balance of probabilities.
Two elements are required under s 71A(2) for the exception to apply: first, that the accused consumed alcohol after he had ceased to drive; and second, that had he not done so, the proportion of alcohol in his breath or blood would not have exceeded the prescribed limit. In this case, the prosecution accepted that the accused had applied Bonjela gel after he had stopped driving, so the dispute focused on the second element—whether the post-driving gel application was the cause of the elevated breath alcohol reading.
In addition, the appeal raised issues about the administration of the breathalyser test. The accused contended that there were improprieties in how the breathalyser was administered, including matters relating to whether the administering officer observed a waiting period before conducting a second test after an error message, and whether two valid BEA results were obtained. These issues were relevant because they could affect the reliability of the breath test evidence used to establish the statutory presumption.
How Did the Court Analyse the Issues?
The High Court began by framing the statutory structure of the RTA drink-driving regime. The court emphasised that s 71A(1) creates a presumption linking the breath sample to the alcohol level at the time of driving. This presumption is not lightly displaced. The accused therefore had to bring himself squarely within s 71A(2), and the burden was on him to prove the exception on a balance of probabilities. The court’s analysis thus focused on whether the evidence established a causal link between the post-driving Bonjela gel application and the BEA reading, sufficient to show that without the gel the reading would have been below the prescribed limit.
On the factual side, the court accepted that the accused had applied Bonjela gel after he ceased driving. The live question was whether the gel could have produced a BEA reading of 75µg/100ml by causing “mouth alcohol” to be detected as “breath alcohol”. The court considered the scientific and expert evidence on the ability of the Dräger Alcotest 9510 SG machine to distinguish between these two categories. The accused’s argument relied on the proposition that gel trapped in the mouth could elevate the measured breath alcohol level, thereby explaining the reading despite a lower true alcohol level at the time of driving.
The court examined multiple sub-issues raised by the accused. One was whether the accused burped or belched during the administration of the breathalyser test. The accused suggested that such events could have released gel-related alcohol into the breath specimen. The court noted that the prosecution’s evidence did not include observations of burping or belching during the test, and the accused’s case did not fill that evidential gap in a way that undermined the reliability of the BEA reading. Another sub-issue concerned the timing between the last application of Bonjela gel and the breathalyser test. The court assessed whether the temporal gap was consistent with the gel having a sufficient effect to raise the measured breath alcohol concentration above the statutory threshold.
A further sub-issue concerned the accused’s claim that Bonjela gel had become trapped in the crack-line of his upper right molar during the breathalyser test. The court considered whether the HSA expert evidence contradicted the evidence that the Dräger machine could distinguish “mouth alcohol” from “breath alcohol”. The court’s approach was to evaluate whether the expert evidence, taken as a whole, supported the proposition that gel trapped in the mouth could meaningfully affect BEA readings in the manner alleged by the accused. The court found that the HSA expert’s evidence did not contradict the evidence that the Dräger Alcotest 9510 SG machine was able to distinguish between mouth and breath alcohol for the purposes of measurement.
The court also considered the accused’s post-driving application narrative, including the claim that the gel was eliminated from his mouth within 20 minutes of the latest application and the implications of that for causation. The court weighed this against the scientific evidence on how the machine detects BrAC results from breath specimens and the impact of Bonjela gel upon those readings. In doing so, the court treated the accused’s explanation as requiring more than a plausible story; it required proof that, absent the gel, the breath alcohol concentration would not have exceeded 35µg/100ml. The court concluded that the accused did not meet that evidential burden.
Finally, the court addressed procedural complaints about the administration of the breathalyser test. The accused argued that the administering officer failed to observe a waiting period before performing a second breathalyser test after an error message for the first test, and that the officer failed to obtain two valid BEA results rather than only one. The court’s analysis treated these matters as potentially relevant to the integrity of the evidence, but it did not accept that the alleged improprieties, even if established, were sufficient to displace the statutory presumption or to prove the s 71A(2) exception. In effect, the court found that the accused’s case remained unproven on the critical causal element: that without the gel, the breath alcohol level would have been below the prescribed limit.
What Was the Outcome?
The High Court dismissed the accused’s appeal against both conviction and sentence. The practical effect was that the District Court’s conviction under the drink-driving charge remained intact, and the sentence imposed by the District Court continued to apply.
As reflected in the proceedings below, the District Court had sentenced the accused to three weeks’ imprisonment and a fine of $6,000 (in default 12 days’ imprisonment). The court also disqualified the accused from holding or obtaining all classes of driving licences for four years, commencing from the date of release. The High Court’s dismissal meant that these orders were not disturbed.
Why Does This Case Matter?
This decision is significant for practitioners because it reinforces the strict evidential burden placed on an accused person seeking to rebut the s 71A(1) presumption through the s 71A(2) exception. While Bonjela gel defences have been litigated before, Tham Saik Mun Simon v PP illustrates that courts will scrutinise not only whether the accused applied the gel after driving, but also whether the accused can prove—through reliable scientific and factual evidence—that the gel was the cause of the measured breath alcohol concentration exceeding the statutory threshold.
The case also highlights how courts evaluate scientific evidence about breath testing technology. The decision shows that the ability of the Dräger Alcotest 9510 SG machine to distinguish mouth alcohol from breath alcohol is central to the analysis. Where the expert evidence supports that distinction, an accused’s narrative about gel trapping, timing, or oral events such as burping will require corroboration or persuasive proof to overcome the statutory presumption.
For defence counsel, the case underscores the importance of addressing evidential gaps—particularly those relating to what occurred during the breath test and the timing of gel application. For prosecutors, it demonstrates the value of comprehensive expert evidence and careful attention to the procedural administration of breathalyser tests. Overall, the judgment serves as a useful reference point for future drink-driving appeals involving post-driving oral applications and challenges to the reliability of BEA results.
Legislation Referenced
- Criminal Procedure Code (Cap 68, 2012 Rev Ed), s 267(1)
- Road Traffic Act (Cap 276, 2004 Rev Ed), s 67(1)(b)
- Road Traffic Act (Cap 276, 2004 Rev Ed), s 71A(1)
- Road Traffic Act (Cap 276, 2004 Rev Ed), s 71A(2)(b)(ii)
Cases Cited
- [2023] SGDC 15
- [2023] SGHC 179
Source Documents
This article analyses [2023] SGHC 179 for legal research and educational purposes. It does not constitute legal advice. Readers should consult the full judgment for the Court's complete reasoning.