6 Drug Driving Charges That Were Dropped, Explained

A positive roadside swab or laboratory finding "over the limit" may make it seem as though the outcome has already been determined. That is not necessarily the case. Drug driving prosecutions depend on a sequence of forensic and procedural stages: the roadside test, collection of blood, laboratory testing, and disclosure of the evidence to the defence. A failure at any stage can cause the prosecution to fail before a verdict is reached.

Drug Driving Solicitors has acted for clients in dozens of drug driving matters that resulted in discontinuance, dismissal, or acquittal. The following six examples from the firm's case history show why each prosecution could not continue.

1. The Blood Result Was Below the Legal Limit: R v Singh, Swindon Magistrates' Court [Case Discontinued, December 2022]

In an unusual matter, Mr Singh's blood sample was reported as being below the legal limit, but he was nevertheless charged with the separate offence of driving while unfit through drugs. The allegation was based in part on statements he made during a police interview months later. Professor Atholl Johnston was instructed as an expert and concluded that the concentration identified in Mr Singh's blood did not align with the amount he said he had taken and was unlikely to have had much effect on him. Together with a separate mistake in the hospital paperwork, this led the prosecution to discontinue the case.

Why it matters: a charge does not itself establish that the evidence supports it. A result below the limit, or expert evidence about the likely effect of a particular level on a person's driving ability, may defeat a prosecution resting on less secure grounds than first appears.

2. A Medical Explanation Was Not Properly Considered: R v Franklin, Cambridge Magistrates' Court [Case Discontinued, April 2022]

Mr Franklin faced a charge of failing to provide a specimen after informing police that he had a needle phobia. Once a person raises a potential medical reason for being unable to provide a sample, the law requires a medical professional to assess whether that reason amounts to a reasonable excuse. In this case, no medical professional was asked to carry out that assessment. An expert report, based on Mr Franklin's medical records and a consultation with him, confirmed that the phobia was genuine. In light of that evidence and its own procedural failing, the prosecution withdrew the case before trial.

Why it matters: a "failure to provide" allegation is not automatically criminal. Where there is a genuine medical reason, police must ensure it is properly assessed. If they fail to do so, their entire case may be weakened.

3. The 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" for cocaine. However, that is not the way a positive result appears on that device: a true positive result shows two red lines. Elsewhere, the officer's account was also inconsistent about the drug for which the test was said to be positive. Those contradictions were brought out during cross-examination at trial. The prosecution then accepted it could no longer prove that the roadside test was positive, undermining the legal basis for requiring a blood sample from the outset. No further evidence was presented.

Why it matters: roadside testing and the evidence of officers who record those results can be challenged in the same way as any other evidence. Contradictions in an officer's description of the test, including apparently minor ones, may be sufficient to unravel the prosecution.

4. The Prosecution Failed to Meet Its Disclosure Timetable: Mr Sharpe [Case Discontinued, October 2018]

After Mr Sharpe pleaded not guilty, the court imposed a clear timetable requiring the prosecution to disclose its forensic report and the material behind it. The first deadline passed without compliance. At a later hearing, further directions were given, but these too were not met. When the matter reached a preliminary hearing only weeks before trial, the prosecution still had not complied and chose to discontinue rather than proceed with its evidence in disorder.

Why it matters: the Criminal Procedure Rules impose genuine duties on the prosecution to disclose evidence within the required time. Repeated non-compliance is not merely a procedural point: courts have repeatedly prevented the prosecution from relying on evidence disclosed too late, and that can be fatal to the case.

5. There Was Insufficient Blood Available for Analysis: R v CH, Bexley Magistrates' Court [Case Discontinued, November 2020]

Mr H sent a portion of his own blood specimen to an independent forensic toxicologist. The expert's finding was clear: the sample did not contain enough blood to permit a valid analysis. After this opinion, together with a formal defence statement, was provided to the Crown Prosecution Service, the case was discontinued approximately a week before trial.

Why it matters: strict rules govern the quantity, handling, and division of a blood sample. Testing a person's own portion independently may reveal issues that the prosecution laboratory did not identify.

6. The Laboratory's Accreditation Had Been Lost During the Case: R v LT, Llandudno Magistrates' Court (March 2021)

A number of the firm's cases depended on the same issue: the laboratory that tested the blood sample had lost its UKAS accreditation to conduct the particular tests required under section 5A of the Road Traffic Act 1988. In Mr T's matter, this was discovered only after the prosecution served its own analytical data pack, which was then reviewed. Once the loss of accreditation was identified, the reliability of the entire analysis became questionable. The prosecution sought an adjournment on the day of trial, but the court refused and no evidence was offered.

Why it matters: an "above the limit" finding is only as reliable as the laboratory that produced it. Where the laboratory did not have the correct accreditation to perform the test, the figure in the report may not survive scrutiny in court.

What These Cases Have in Common

These six prosecutions were not abandoned because police "changed their mind." Each failed for a distinct and provable reason: an under-limit result, an unassessed medical explanation, unreliable officer evidence, missed disclosure deadlines, an inadequate sample, or an unaccredited laboratory. In every instance, the outcome depended on a defence team knowing where to examine the evidence.

For anyone facing a drug driving charge, the circumstances of the stop, the sample, and the evidence underlying the allegation may carry far greater importance than a single figure in a laboratory report. Obtaining advice from a specialist solicitor at an early stage provides the best opportunity to establish whether one of these issues may also apply.

This article provides general information only and is not legal advice. Every case depends on its own facts.