Why These 6 Drug Driving Cases Were Dropped

A roadside swab that is positive, or a laboratory result described as "over the limit", may make a conviction seem inevitable. That is not the case. A drug driving prosecution depends on a sequence of forensic and procedural stages: the roadside test, collection of blood, laboratory testing and disclosure of that material 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 are six real cases from the firm's own history, each showing the particular issue that led to the case falling apart.

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

Mr Singh's case was unusual because his blood specimen produced a result below the legal limit. Even so, he was charged with the distinct offence of driving while unfit through drugs, partly because of statements he made during a police interview months afterwards. Acting as an expert, Professor Atholl Johnston concluded that the blood level was inconsistent with the amount Mr Singh said he had taken and was unlikely to have affected him significantly at all. Alongside a separate mistake in the hospital's paperwork, this led the prosecution to discontinue the case.

Why it matters: a charge does not necessarily mean the available evidence supports it. A result under the limit, or expert consideration of what a particular level would realistically mean for a person's driving ability, may dismantle a charge founded on less secure evidence than it initially appears.

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

A number of the firm's cases depended on the same finding: the laboratory that had tested the blood sample no longer held UKAS accreditation for the particular tests required by section 5A of the Road Traffic Act 1988. In Mr T's case, the issue emerged only after the prosecution served its own analytical data pack and it was reviewed. Establishing that the accreditation had been lost called the reliability of the entire analysis into question. The prosecution requested an adjournment on the trial date, but the court declined it and no evidence was offered.

Why it matters: an "above the limit" finding has value only if the laboratory producing it was properly accredited. Where the lab lacked accreditation for the relevant test, the figure recorded in the report may not withstand scrutiny in court.

3. The Police Officer's Evidence Could Not Be Sustained: R v Lewis, Manchester Magistrates' Court [Case Dismissed, February 2023]

In Mr Lewis's case, the arresting officer stated that the roadside drug test had shown a "blue line" for cocaine. However, that device does not display a positive result in that way, as a true positive is indicated by two red lines. Elsewhere, the officer's statement was 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 that it could no longer prove the roadside test had been positive, undermining the legal justification for requiring a blood sample in the first place. No further evidence was offered.

Why it matters: roadside test findings and the accounts given by officers can be challenged in the same way as other evidence. Differences in an officer's description of the test, including issues that may seem minor, can be sufficient to unravel the prosecution's case.

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 schedule requiring the prosecution to disclose both its forensic report and the underlying material. The first deadline passed without compliance. Further directions were issued at a later hearing, yet those were not met either. When the case reached a preliminary hearing only weeks before trial, the prosecution still had not complied. Rather than continue without the evidence in proper order, it discontinued the case.

Why it matters: under the Criminal Procedure Rules, the prosecution has meaningful duties to disclose evidence within the required time. Repeated non-compliance is not merely a procedural technicality. Courts have repeatedly prevented the prosecution from relying on evidence served too late, and that can be fatal to its case.

5. 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 he told police that he had a needle phobia. Once a possible medical reason for not providing a sample has been raised, the law requires a medical professional to consider whether it gives rise to a reasonable excuse. No medical professional was asked to carry out that assessment in his case. 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 omission, the prosecution dropped the case before trial.

Why it matters: a "failure to provide" charge is not automatically an offence. Where there is a genuine medical reason, police must ensure it is assessed properly. If they fail to do so, the prosecution's whole case may be undermined.

6. The Sample Did Not Contain Enough Blood for Testing: R v CH, Bexley Magistrates' Court [Case Discontinued, November 2020]

Mr H sent part of his own blood specimen to an independent forensic toxicologist. The expert reached a clear conclusion: the sample did not contain enough blood for a valid analysis to be performed. This was presented to the Crown Prosecution Service together with a formal defence statement. About a week before trial, the case was discontinued.

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

What Connected These Cases

These six cases did not end because the police "changed their mind." Instead, each involved a distinct issue capable of being proved: an unaccredited laboratory, missed disclosure deadlines, an inadequate sample, an unexamined medical reason, a result inconsistent with the charge or evidence that could not withstand scrutiny. In each matter, the defence team had to know precisely where to investigate.

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

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