Why Choose Us
- Ranked in the top 3 law firms by Trustpilot
- Nationwide Legal Coverage
- Free Consultation
- Fixed Fee Terms
- Competitive Rates
- Flexible Payment Plans
- Trusted Legal Care
- UK’s Leading Motoring Solicitors
Can You Drive Whilst Taking Medically Prescribed Cannabis?
5 out of 5
Our customers rate us
“EXCELLENT”
AS SEEN ON
27.03.2025
Can You Drive Whilst Taking Medically Prescribed Cannabis?
Yes, you can legally drive in the UK with a prescription. However, Medical Cannabis Driving Law is complex, and many drivers – and even some police officers – misunderstand the rules.
If you are stopped and tested, you will almost certainly test “Over the Limit” for THC, as the legal limit is set near zero (2µg/L). However, patients are protected by the Statutory Medical Defence under Section 5A of the Road Traffic Act 1988.
This guide explains exactly how to use that defence and what to do if you are stopped by the police.
Medical Cannabis Driving Law: The Two Offences
To stay legal, you must understand the difference between the two main offences in Medical Cannabis Driving Law. Your prescription protects you from one, but not the other.
| The Offence | The Law | Does a Prescription Protect Me? |
|---|---|---|
| 1. Over the Specified Limit (Zero Tolerance Limit: 2µg/L) |
Section 5A, Road Traffic Act 1988 | YES (Statutory Defence) |
| 2. Driving While Impaired (Unfit to Drive) |
Section 4, Road Traffic Act 1988 | NO (Strict Liability) |
Warning: Do Not Drive If Impaired
If your medication makes you drowsy, affects your reaction times, or creates “brain fog,” you must not drive. If police prove your driving was “impaired” (e.g., poor lane discipline, slow reactions), your prescription is not a defence.
The Statutory Defence in Medical Cannabis Driving Law
Because the legal limit for THC is so low, almost every patient will technically be “Over the Limit.” However, under Section 5A(3) of the Road Traffic Act 1988, you are not guilty if you can prove three things:
The 3-Point Defence Checklist
- ✔Legally Prescribed: The cannabis was prescribed or supplied to you for medical or dental purposes by a registered clinician.
- ✔Correct Use: You took the medication in accordance with the instructions given by the prescriber (e.g., method of administration) and the manufacturer.
- ✔Lawful Possession: Your possession of the drug was lawful immediately before taking it.
Crucially: If you “top up” your prescription with street cannabis (the illicit market), you lose this defence entirely. Forensic toxicology can often distinguish between pharmaceutical-grade cannabis profiles and street strains.
What to Do If Stopped by Police
Roadside drug tests (DrugWipes) give a simple “Pass/Fail” result. They cannot tell if you have a prescription. Follow these steps:
- Be Polite & Clear: Inform the officer immediately that you are a medical cannabis patient.
- Show Evidence: Present your current prescription (paper copy or app), the original packaging with your name on the label, and your ID.
- The Blood Test: If you fail the roadside swab, you may still be arrested and taken for a blood test. Do not panic and do not refuse. Refusing to provide a sample is a separate offence with a guaranteed ban.
- Reference the Defence: State clearly during your interview that you are claiming the Statutory Medical Defence under Section 5A.
Common Questions & Answers – Prescribed Drugs & Driving
Summary: Your Right to Drive is Conditional
The law explicitly acknowledges your right to access medical treatment. Section 5A was drafted specifically to ensure that patients are not criminalised for taking their prescribed medication.
However, this protection is not absolute. Your defence relies entirely on your strict adherence to the rules: taking the medication exactly as prescribed and ensuring you are never impaired while driving. Treat your prescription with the same caution as you would alcohol; if you feel drowsy, slow, or “different,” do not get behind the wheel.
Worried About a Drug Driving Charge?
If you have been arrested despite your prescription, do not accept the charge. Our specialist solicitors can help establish your statutory defence.
Follow me here at LinkedIn
I am a criminal lawyer with over 25 years of experience and specialising in the defence of Road Traffic (driving) prosecutions and the founder and Senior Partner of Caddick Davies Solicitors.
Latest posts by Neil Davies (see all)
- Common Myths: Speeding & Speed Cameras - October 1, 2025
- Can Needing To Go To The Toilet Provide A Defence To A Motoring Offence - June 19, 2025
- Can I Drive With MOT Advisories? The Legal Position Explained - June 19, 2025
We have been successfully representing clients in motoring courts nationwide
Contact us for a free consultation, our expert solicitors will be able to discuss your case and advise on legal options.
Birmingham
Bradford
Bristol
Carlisle
Cardiff
Chelmsford
Huddersfield
Hull
Manchester
Liverpool
Leeds
London
Newcastle
Norwich
Nottingham
Sheffield
