Since the change in legislation allowing cannabis-based products for medicinal use (CBPMs) to be prescribed in 2018, the DVLA hasn’t issued any specific guidance related to these medicines.
This, along with the lack of training and guidelines for police officers, has contributed to a great deal of confusion when it comes to driving with a prescription for CBPMs.
In some cases, this has led to patients being arrested and convicted of driving-related offences
Richard List, a retired Detective Chief Superintendent and Controlled Drug Liaison Officer who has been involved in developing national police guidance on medical cannabis, says a lack of awareness among officers remains a key challenge.
“The problems that are facing the police are the same problems that are facing the police in relation to medical cannabis in general,” he told Cannabis Health.
“And that is there is a lack of knowledge, a lack of understanding, and as a result, a lack of acceptance of medical cannabis.”
List says this becomes more complex in relation to driving, where officers must navigate specific drug-driving legislation and make decisions around impairment, testing and enforcement, which can result in inconsistencies in how prescribed patients are dealt with.
What does the law say about driving and medical cannabis?
DVLA guidelines treat CBPMs the same as other prescription drugs.
Under Section 4 of the Road Traffic Act (1988) it is illegal to drive with prescription drugs in your body if it impairs your driving.
It is also an offence to drive if you have over the specified limits of certain non-prescription drugs in your blood even if there is no evidence of impairment.
Under section 5A of the Road Traffic Act 1988, driving with more than 2 micrograms of THC per litre of blood is a criminal offence. The prosecution does not have to prove that the individual’s driving was impaired.
Patients who test above the limit have a Statutory Medical Defence under Section 5A, meaning they are not guilty if the drug was lawfully prescribed, taken in accordance with directions, and possession was lawful. However, this is a defence, not an exemption, and must be raised evidentially at court.
It depends on the patient having followed prescribing directions and being fit to drive, and cannot prevent a roadside stop, a blood test, arrest or charge in the first place.
| Section 4 – Driving while impaired | Section 5A – Driving over the specified drug limit | |
|---|---|---|
| The offence | Driving, attempting to drive, or being in charge of a vehicle while unfit to drive through drugs. | Driving, attempting to drive, or being in charge of a vehicle with a specified controlled drug above the legal limit. For THC, the specified blood limit is 2µg/L. |
| What must the prosecution prove? | That the person was unfit to drive because of a drug and their ability to drive properly was impaired. | That the concentration of the specified drug in the person’s blood or urine was above the prescribed limit. The prosecution does not need to prove impairment. |
| What defence exists? | There is no equivalent Section 5A statutory medical defence. However, the prosecution must establish that the person’s driving ability was impaired through drugs. | A statutory medical defence may apply where the drug was prescribed or supplied for medical purposes and was taken in accordance with the relevant directions, subject to the requirements of Section 5A. |
Do I need to notify the DVLA about my medical cannabis prescription?
Patients are not generally required to inform the DVLA of their medical cannabis prescription, unless it is related to a condition which could affect their driving. UK law requires that drivers tell the DVLA about any medical condition that could potentially affect their driving, and has an online service to help you check if your condition needs to be reported.
Read the full article
https://cannabishealthnews.co.uk/2026/09/04/medical-cannabis-and-driving-in-the-uk-the-law-the-science-and-your-rights/
