6 Drug Driving Cases the Prosecution Dropped and Why
A positive roadside swab or laboratory finding showing a driver "over the limit" may make a prosecution seem inevitable. However, the outcome is not predetermined. Drug driving cases depend on a sequence of forensic and procedural stages, including the roadside test, collection of the blood specimen, laboratory testing, and disclosure of the evidence to the defence. A failure at any point in that sequence can cause the prosecution's case to fall apart before a verdict is reached.
Drug Driving Solicitors has acted for clients in dozens of drug driving matters that concluded with discontinuance, dismissal, or acquittal. The following six cases come from the firm's own case history and illustrate the particular issue that caused each prosecution to fail.
1. A Genuine Medical Explanation Was Not Properly Evaluated R v Franklin, Cambridge Magistrates' Court [Case Discontinued, April 2022]
Mr Franklin faced a charge of failing to provide a specimen after informing the police that he suffered from a needle phobia. When a person identifies a potential medical reason for being unable to provide a sample, the law requires a medical professional to assess whether that reason constitutes a reasonable excuse. In this case, however, no medical professional was brought in to carry out that assessment. An expert later reviewed Mr Franklin's medical records, consulted with him, and produced a report confirming that the phobia was genuine. In light of that evidence and the procedural failure surrounding the assessment, the prosecution discontinued the case before trial.
Why this is significant: failing to provide a specimen does not automatically establish an offence. Where a genuine medical reason exists, the police must ensure it is properly assessed. Failure to obtain that assessment may seriously weaken the prosecution's case.
2. The Arresting Officer's Evidence Could Not Withstand Scrutiny R v Lewis, Manchester Magistrates' Court [Case Dismissed, February 2023]
In Mr Lewis's case, the arresting officer stated that the roadside drug test displayed a "blue line" indicating cocaine. That description did not correspond with the way the device actually displays a positive result, which is shown by two red lines. Elsewhere in the officer's evidence, there were also contradictions concerning which drug had supposedly produced the positive test. Cross-examination at trial exposed these inconsistencies. The prosecution ultimately accepted that it could no longer establish that the roadside test had been positive, undermining the legal basis on which the blood sample had been requested. No additional evidence was offered.
Why this is significant: both roadside test results and the officers responsible for documenting them are open to challenge. Even apparently minor inconsistencies in an officer's description of the testing process can become important enough to undermine the prosecution.
3. The Blood Result Was Below the Legal Limit R v Singh, Swindon Magistrates' Court [Case Discontinued, December 2022]
Mr Singh's case was unusual because analysis of his blood specimen showed a result below the legal limit. Despite this, he was charged with the separate offence of driving while unfit through drugs, with the allegation relying partly on statements he had made during a police interview months afterward. Professor Atholl Johnston was instructed as an expert and concluded that the concentration identified in Mr Singh's blood did not correspond with the amount he had described taking and was unlikely to have significantly affected him. Together with a separate mistake in the hospital's paperwork, this evidence ultimately resulted in the prosecution discontinuing the case.
Why this is significant: the fact that a charge has been brought does not establish that the supporting evidence is sufficient. Where a result is below the legal limit, expert examination of what the detected concentration would realistically mean for a person's ability to drive can expose weaknesses in a charge that initially appears stronger than it is.
4. The Laboratory Lost Its Accreditation During the Proceedings R v LT, Llandudno Magistrates' Court (March 2021)
A number of the firm's cases were affected by the discovery that the laboratory responsible for analysing blood specimens had lost its UKAS accreditation for the particular testing required under section 5A of the Road Traffic Act 1988. In Mr T's case, the problem was identified only after the prosecution provided its own analytical data pack and the material was examined. Establishing that the laboratory had lost the relevant accreditation raised questions about the reliability of the analysis as a whole. On the trial date, the prosecution sought an adjournment, but the court refused the request. The prosecution then offered no evidence.
Why this is significant: a laboratory result showing that someone was "above the limit" depends on the reliability and status of the laboratory responsible for producing it. If the laboratory did not hold the appropriate accreditation to conduct the relevant test, its reported figure may not withstand scrutiny in court.
5. The Blood Sample Was Too Small for Valid Testing R v CH, Bexley Magistrates' Court [Case Discontinued, November 2020]
Mr H arranged for his portion of the blood specimen to be examined by an independent forensic toxicologist. The expert reached a clear conclusion: the specimen did not contain enough blood to permit a valid analysis. After this finding was presented to the Crown Prosecution Service together with a formal defence statement, the prosecution discontinued proceedings approximately one week before the scheduled trial.
Why this is significant: strict requirements apply to the quantity, handling, and division of blood specimens. Having the defendant's own portion independently tested may reveal defects that were not identified by the prosecution's laboratory.
6. Repeated Disclosure Deadlines Were Missed by the Prosecution Mr Sharpe [Case Discontinued, October 2018]
After Mr Sharpe pleaded not guilty, the court established a timetable requiring the prosecution to provide its forensic report and the supporting material. The first deadline passed without compliance. Further directions were issued at another hearing, but those requirements were missed as well. When the matter eventually reached a preliminary hearing only weeks before the scheduled trial, the prosecution had still failed to comply with the disclosure timetable. Rather than continue without its evidence properly in order, the prosecution discontinued the case.
Why this is significant: the Criminal Procedure Rules impose genuine duties on prosecutors to provide evidence within the required timeframe. Repeated failures to meet disclosure deadlines are not merely procedural details. Courts have repeatedly prevented the prosecution from relying on evidence served too late, and the loss of that evidence can prove fatal to a case.
What These Cases Have in Common
The police did not simply "change their mind" in any of these six matters. Each prosecution ended because of an identifiable and demonstrable problem: a medical explanation that was never properly assessed, officer evidence that failed under scrutiny, a blood result below the legal limit, a laboratory without the necessary accreditation, an inadequate blood specimen, or repeated failures to comply with disclosure deadlines. In each instance, identifying the weakness depended on a defence team knowing which aspects of the evidence and procedure required close examination.
For anyone facing a drug driving allegation, the circumstances surrounding the stop, the handling of the specimen, and the evidence supporting the charge can be considerably more important than a single figure contained in a laboratory report. Seeking advice from a specialist solicitor at an early stage provides the best opportunity to establish whether similar evidential or procedural problems may affect the case.
This material provides general information only and should not be treated as legal advice. The outcome of every case depends on its individual facts.
