Drink driving or drug driving cases often depend heavily on scientific evidence. A blood, urine or breath result may appear straightforward, but forensic evidence still needs to be properly obtained, analysed, interpreted and explained.
A forensic expert can help solicitors understand whether a drink and drug driving result is reliable, whether the correct procedures were followed, and whether there are scientific issues that may assist the defence.
At Bericon Forensics, our experts provide independent forensic reports for legal professionals across the UK, including cases involving drug driving, toxicology and alcohol-related evidence.
When might a drink driving or drug driving result be challenged?
A forensic expert may be instructed where there is a question about the reliability, interpretation or timing of a result. This does not mean every case can be challenged successfully, but it can help identify whether there is a genuine scientific issue.
Common areas for review include:
✔️whether the sample was taken, stored and analysed correctly
✔️whether the reported result has been properly interpreted
✔️whether the level at the time of driving may have been different from the level at the time of testing
✔️whether medication, medical issues or toxicological factors need to be considered
✔️whether post-driving alcohol or drug consumption may be relevant
✔️whether the prosecution evidence is complete and scientifically sound
✔️In some cases, the expert evidence may support the prosecution result. In others, it may identify uncertainty, limitations or alternative explanations that need to be considered by the court.
Challenging drug driving results
Drug driving cases often involve blood analysis for substances such as cannabis, cocaine, benzodiazepines, ketamine, amphetamine or other controlled drugs. The key question is usually whether the concentration of a specified drug exceeded the legal limit at the time of driving.
However, the timing of drug use, the timing of the blood sample, the individual’s pattern of use, and the way the drug is metabolised can all be important.
A forensic toxicology expert may be able to comment on issues such as:
✔️whether the drug level could have been below the legal limit when driving
✔️whether post-driving drug consumption could explain the result
✔️whether the analytical data has been correctly acquired, processed and interpreted
✔️whether the result is consistent with the account provided
✔️whether prescribed medication or other factors may be relevant
Bericon Forensics provides expert assistance in drug driving cases and can review Crown analytical evidence where appropriate.
Post-driving drug consumption
In some cases, a defendant may state that drugs were consumed after driving but before the sample was taken. This can raise an important forensic question: was the person over the legal limit at the time they drove, or did the later consumption contribute to the result?
A forensic expert may be asked to consider the timing, quantity, type of drug, blood result and any available witness or case information. This type of assessment is complex and depends heavily on the facts of the case.
Bericon Forensics has experience preparing reports in relation to post-driving drug consumption where this issue arises.
Challenging drink driving results
Drink driving cases may involve breath, blood or urine evidence. Although many alcohol cases appear simple, expert evidence can still be important where there are questions about timing, procedure, alcohol consumption, medical issues or the interpretation of results.
A forensic expert may consider:
✔️the time of driving compared with the time of testing
✔️whether alcohol was consumed after driving
✔️whether the result is consistent with the account given
✔️whether the correct testing procedure was followed
✔️whether blood or urine alcohol calculations are required
✔️whether there are issues with sample handling or continuity
Expert evidence can be particularly useful where the case involves “hip flask” style arguments, back-calculations, rising blood alcohol, disputed timing, or unusual factual circumstances.
Why expert review matters
Forensic evidence should be independent, balanced and scientifically grounded. A good expert does not simply look for a defence point. Their role is to assess the evidence fairly and explain what the science can and cannot support.
An expert report may help solicitors to:
✔️identify whether there is a realistic issue to raise
✔️understand the strength of the prosecution evidence
✔️narrow the issues before court
✔️advise the client more clearly
✔️support representations or case preparation
✔️provide court-ready expert evidence where required
This can be valuable at an early stage, especially before a case progresses unnecessarily or important deadlines are missed.
What information does the expert need?
To review a drink drinking or drug driving case properly, a forensic expert may need some or all of the following:
✔️prosecution laboratory report
✔️MGDD forms or police procedure documents
✔️custody record
✔️witness statements
✔️toxicology results
✔️details of medication
✔️account of alcohol or drug use
✔️timings of driving, arrest, sample collection and testing
The more complete the information, the more useful the expert review is likely to be.
Can a forensic expert get the case dismissed?
A forensic expert does not decide the outcome of a case. That is a matter for the court. However, expert evidence can make a significant difference where there is a genuine scientific issue.
An expert may find that the result is reliable and properly interpreted. They may also find that there are limitations, uncertainties or alternative explanations that should be considered. In some cases, this can assist with case strategy, negotiations, trial preparation or the overall defence.
Instructing Bericon Forensics: Drink or Drug Driving
Bericon Forensics provides independent forensic expert witness services for solicitors across the UK. Our experts assist with drink driving, drug driving, forensic toxicology and related criminal defence matters.
We can help with:
✔️reviewing prosecution alcohol or drug evidence
✔️assessing drug driving results
✔️considering post-driving consumption issues
✔️preparing court-ready expert reports
✔️advising on toxicology evidence
✔️supporting solicitors with clear, practical forensic opinion
To discuss a case, visit our Drug Driving Expert page, our Toxicology & Drug Expert Witness page, or contact Bericon Forensics directly.
Conclusion
A forensic expert can challenge, review or explain a drink drinking or drug driving result where there is a scientific issue to consider. The key question is whether the result has been properly obtained, analysed and interpreted, and whether it accurately reflects the position at the time of driving.
Early expert input can help solicitors understand the evidence, identify potential issues and prepare the case properly.
