Since medical cannabis was legalised in the UK in November 2018, thousands of patients have gained legal access to cannabis-based medicines for the first time in almost 50 years. Despite this landmark move, however, education around the topic has remained significantly underdeveloped, leaving patients and even the authorities unsure about the rules when it comes to medical cannabis prescriptions.
One such topic that continues to produce confusion for medical cannabis patients and their families is the rules around driving. Does gaining a medical cannabis prescription mean you have to say goodbye to the convenience of getting behind the wheel? Can you get into trouble with the police? These are all questions that medical cannabis patients may find themselves asking after filling their first prescription.
Luckily, there are resources available to clear up any confusion; in this article, we will take a deep dive into UK legislation relating to driving and medical cannabis use, with the aim of telling you everything you need to know about driving when you have a medical cannabis prescription.
Medical cannabis side effects and driving
Depending on the levels of THC present, medical cannabis use can cause significant side effects that can affect a patient’s driving ability. For example, common side effects of THC exposure include sedation, decreased cognitive function, slower response times, and drowsiness. The extent of these side effects can differ significantly from patient to patient; however, you should never drive if you are impaired to any extent.
In contrast, studies found that CBD is not associated with driving impairment, so if you are prescribed a CBD-based medical cannabis product, you may face fewer restrictions when it comes to driving. Nevertheless, it is important to be mindful that CBD-dominant products can contain small levels of THC that – while may not cause impairment – may still show up on a drug test.
So, what does the actual law say when it comes to medical cannabis and driving? And what happens if you get pulled over?
UK law regarding medical cannabis and driving
UK law states that you are obliged to inform the Driver and Vehicle Licensing Agency (DVLA) of any condition that could potentially affect your driving. Prescribers are required to offer each patient guidance based on their specific circumstances – including their medical condition and the medicines prescribed to them.
NatCen’s government-sanctioned report on “Medical Cannabis and road safety” states: “In line with DVLA guidance, prescribers should give patients advice on driving while using medical cannabis, as they would with any other medication.” This includes being aware of possible interactions with other medications and monitoring patients’ responses to their medication – including those that could potentially impair driving.
So, to sum up: it is not an offence for legal medical cannabis to drive, so long as they are not impaired and they are following the guidance provided by their prescriber. But that isn’t to say that medical cannabis patients definitely won’t face legal challenges if they are pulled over by the police.
What if I get stopped by the police?
Regardless of impairment, which is thought to only last for around four hours or less, THC can remain in the blood, saliva, and hair for weeks after consumption. As a result, medical cannabis patients who are pulled over by the police and asked to take a roadside drug test may find themselves in a tricky situation.
Being convicted of drug driving in the UK can mean a minimum one-year driving ban, an unlimited fine, up to 6 months in prison and a criminal record. So, it is understandable why medical cannabis patients may be concerned about driving. The good news is, medical cannabis patients who are not impaired and who are following the advice of their prescribers have a statutory defence that will protect them from prosecution.
To avoid any complications, it is recommended that medical cannabis patients keep a copy of their prescription in their car at all times. This will inform the police that you have a qualifying condition and legal access to cannabis for medicinal purposes. Furthermore, the ‘Seed our Future’ Campaign was launched to provide patients with a ‘Statement of Fact’ document that sets out their statutory defence relating to their cannabis use.
In 2021, the Seed our Future Campaign aided four medical cannabis patients who had been charged with drug driving. In three of the cases, the campaign’s report stated that the officers concerned were unaware that the law regarding medical cannabis had changed. Incidences such as this highlight the need for further education – not only among the general public but among the authorities, too.
How is impairment determined?
As we mentioned earlier, if you are not impaired while driving after taking medical cannabis, you have a statutory defence to protect you from prosecution. But how do the police determine your impairment? This is a question that contributes to significant confusion and debate – particularly as the vast majority of available data on the subject relates to the use of recreational cannabis.
This remains a grey area across all legal cannabis jurisdictions. The fact is, there is no reliable way to measure cannabis impairment. A roadside drug test will not test for impairment, it will only test for the presence of THC. The legal limit of THC is 2 mg/litre of blood. However, THC can remain in your blood long after impairment has subsided, which can leave patients and the authorities alike in a difficult situation.
The key takeaways
The important thing to remember though is that, as long as you are taking your medical cannabis in accordance with your prescriber’s guidance, and have proof of your prescription, the police should have no need to escalate the situation further if you are pulled over. Printing off a copy of the Seed our Future campaign’s ‘Statement of Fact’ may also help to resolve the situation more quickly.
There is clearly still a long way to go to eradicate the stigma against medical cannabis and the patients that use it; however, medical cannabis patients can take a little comfort in the fact that, if the worst happens, there are resources available that can help to prevent the situation from going too far.
