Cleared in court: a medical cannabis patient's drug driving appeal

Sal Aziz is a patient who is legally prescribed medical cannabis. In March 2024, police stopped the car he was driving as friends were being taken home from an event. He passed the roadside alcohol test. He told the officer straight away that he was a prescribed patient.

A roadside drug swab showed cannabis, and he was asked to do a set of roadside tasks called a Field Impairment Test. He was arrested. A blood test later showed 3.6 micrograms of THC per litre of blood. The legal limit is 2 micrograms per litre. He was charged under two parts of the Road Traffic Act 1988: section 4 (driving while unfit) and section 5A (driving over the drug limit).

The magistrates' court dropped the section 4 charge but found him guilty of the section 5A offence. He was fined and banned from driving for 36 months. He appealed.

On 10 February 2026, at Winchester Crown Court, Sal Aziz was cleared. The prosecution could not prove, beyond reasonable doubt, that his medical defence did not apply. The prosecution had argued his medicine was unlawful because more than 30 days had passed since the prescription, and because it was past its labelled use-by date. The court rejected this. The pharmacist expert, Umesh Chauhan, agreed that the "30 days" idea is best-practice guidance, not criminal law.

Two parts of the Road Traffic Act 1988 matter here. They ask different questions, and it helps to keep them apart.

The medical defence (section 5A(3))

If you are a lawful patient, you have a defence to the section 5A offence. You need to show three things.

Who has to prove what (section 5A(5))

This is the part patients most often get wrong, and it matters a lot.

What are cannabis medicines?

Cannabis-based medicinal products were made legal to prescribe in the UK in November 2018, as Schedule 2 controlled drugs. They are prescribed by specialist doctors, supplied through regulated pharmacies, and come with records and oversight. They are not the same as illegal cannabis. Forms include dried flower (usually vaporised), oils, and capsules.

Taking medicine "as required"

Many patients take medical cannabis "as required", which means by symptom need, not at fixed times. Patients are given a maximum amount but do not have to use all of it. So a "30-day" supply often lasts much longer. That is normal, not misuse.

Why THC stays in the body

THC is fat-soluble. It stores in body fat and is released slowly over time. So it can show up in blood hours, days, or even longer after use, especially in regular patients. A blood reading is not proof of a current effect.

The limits of the FIT

The Field Impairment Test uses balance and coordination tasks and eye checks. The science raises real concerns: there is no agreed "normal" baseline, it relies heavily on an officer's opinion, and anxiety, stress, tiredness, and surroundings can all affect the result.

The Crown Court allowed the appeal and quashed the conviction. The key question was not whether he was over the limit. He was. The key question was whether the prosecution had disproved the medical defence beyond reasonable doubt. It had not. The judge accepted several clear points.

• The expert evidence was accepted: the 28-day rule is about dispensing, a 30-day supply is about quantity, there is no legal rule to use medicine within 30 days, "as required" use often lasts longer, and medicines can be used past their expiry. That last point is about safety and quality, not a legal rule.
• The defence is only lost if you drive against advice about timing between use and driving. It is not lost for an old prescription date or for the length of supply.
• Being over the limit opens the door to the offence, but it does not defeat the defence.
• Once the defence is raised, the burden sits with the prosecution. Here they relied on assumption, not proof, and so failed.

These problems are not just about one case. They point to wider issues in how drug driving cases involving prescribed medicine are handled.

• Confusing dispensing rules with lawful use, the "30-day" myth.
• Reading "taken as directed" too widely. It only covers driving-timing advice.
• Trusting roadside observations without any medical context.
• Treating the Field Impairment Test as stronger than the science supports.
• Not using the medical information the patient gave at the roadside.
• Escalating too far, with no poor driving and no proven impairment.
• Treating cannabis patients differently from people on opioids or benzodiazepines, who are not routinely tested or arrested just for holding a prescription.
• Too little expert evidence used by the investigation and the prosecution.
• Getting the burden of proof the wrong way round.

For patients

• Carry proof of your prescription where you can: pharmacy labels, clinic letters, or digital records. This helps an officer see your use is lawful early on.
• Follow any driving advice from your clinician. The key legal point is the advice about driving after using your medicine.
• Stay calm and explain your condition and medicine clearly. Symptoms like anxiety, shaking, or trouble concentrating can be misread.
• Know that things may still escalate, even when you are lawful. An officer may not be able to judge the medical defence at the roadside.

If you are charged

• Gather evidence at once: prescription records, clinic letters, pharmacy labels, packaging, proof of ongoing treatment, and any written driving advice.
• Get your clinical records. NHS or clinic notes can be vital, especially if roadside observations have a medical explanation.
• Get legal advice early if you can. Please see the note below about legal aid.
• Consider expert evidence. A pharmacist or clinician can explain prescribing and clear up myths. In this case, expert evidence was central.
• Use this case as a reference: a 30-day supply is not a legal use limit, the defence is only lost if you drove against driving advice, and the prosecution must disprove the defence.
• Keep the focus on the legal test, not the THC number alone.

Legal help and representing yourself

Section 5A is a non-imprisonable offence. So defendants are usually not eligible for legal aid in the magistrates' court. Many patients must pay for a lawyer or represent themselves. That is hard in cases with complex law, medical and pharmacy evidence, and burden-of-proof issues. The full report is written so patients can use it to understand the defence, find the right evidence, challenge wrong assumptions, and make sure the burden of proof is applied correctly.

For police officers

• Take medical disclosures seriously and early. A stated prescription is a possible lawful explanation that needs checking.
• Treat nerves, shaking, and task difficulty with caution. These can be medical, such as anxiety, and are not proof of impairment.
• Treat the Field Impairment Test as a screening tool, not firm evidence, and recognise its limits.
• Think about proportionality. With no poor driving, no proven impairment, and a shown prescription, weigh up arrest and custody carefully.
• Keep decisions in line with the law, which allows prescribed drugs to be present and provides a defence.

For defence solicitors

• Raise the medical defence clearly and early.
• Get prescription records, pharmacy labels, and clinical notes.
• Consider expert evidence to explain prescribing and address myths.
• Challenge assumptions about prescription expiry or duration.
• Put the burden of proof on the prosecution to disprove the defence.

For the Crown Prosecution Service

• Check early whether the medical defence may apply.
• Do not proceed on assumptions about prescribing or medicine duration.
• Get expert evidence where needed, on prescribing or on whether a drug caused impairment.
• Apply the public interest test carefully where impairment is not shown and a lawful prescription exists.
• Apply the burden of proof correctly: disprove the defence with evidence, not inference.

For judges and magistrates

• Apply the law as written, focusing on whether driving happened against driving-timing advice.
• Do not treat prescribing conventions as decisive unless the statute says so.
• Weigh expert evidence properly, especially on technical or clinical points.
• Make sure the prosecution has actually disproved the defence, not just raised doubt.

The law here is clear in principle, but it was misunderstood and misapplied in practice. It took three court hearings, expert help, and a lot of personal effort to reach the right result.

After the arrest, Sal faced a long, uncertain wait with no legal aid. As a non-imprisonable offence, it fell outside routine legal support. The stress affected his health and wellbeing. He was able to keep working, but many people in the same position would not be. Being charged or convicted at the first stage can cost people their job, their finances, and their health, before the law is even applied properly.

The win was possible thanks to a McKenzie Friend, Guy Coxall, and expert pharmacist evidence from Umesh Chauhan. Not everyone can get that help.

Thanks

Sal Aziz thanks: Guy Coxall, McKenzie Friend, for his guidance and commitment; Umesh Chauhan, Superintendent Pharmacist, for clear expert evidence at short notice; Mohammad Wasway, for support as a colleague and friend; his line managers, for their understanding; his family, for their patience; and the wider cannabis community, for advice and encouragement.