Can You Smoke Medical Cannabis in Public?

Q: Is there a legal THC limit in the UK?

Yes, but only for driving. The legal limit is 2 micrograms of THC per litre of blood, but driving while impaired remains an offence — even with a medical prescription.

When medical cannabis is mentioned, many assume that if it’s “legal for medical use,” it can be treated like any other medicine. However, for patients in the UK prescribed cannabis-based medicinal products (CBMPs), the legal and practical rules are often more complex than they seem. One of the most frequently asked questions is: can you smoke medical cannabis in public?

In short: no, in most cases you cannot smoke medical cannabis in public in the UK. Below, we explain why — and what alternatives, rights, and cautions you should be aware of.

Legal & Regulatory Framework: Why “smoking” is not allowed

Cannabis remains a controlled substance

Under the Misuse of Drugs Act 1971, cannabis is classified as a Class B drug. That means possession, supply, import, export or producing cannabis is illegal unless explicitly permitted under law. (House of Commons Library)

Medical cannabis was legalised (in a limited way) in November 2018, via changes to the Misuse of Drugs (Amendment) (Cannabis and Licence Fees) Regulations. (Wikipedia) But that change did not mean that all forms of use became legal.

“Unlawful to self-administer by smoking”

Legal commentary and regulatory guides note that self-administration of a cannabis-based product by smoking is unlawful, except in very narrowly defined research contexts. (CMS Law)

Many medical cannabis providers explicitly state that smoking your prescription invalidates the prescription in the eyes of the law.

Thus, even if you hold a valid medical cannabis prescription, lighting and inhaling (i.e. combusting) the dried plant in public (or private) is prohibited by UK law.

Why this restriction?

There are several practical and regulatory reasons:

Health/safety & public nuisance: Smoking in public is heavily regulated due to second-hand smoke, fire risk, nuisance, and air quality.
Lack of control: Smoking releases variable doses via combustion; vaporisation or oils are more controllable, which is safer medically.
Regulatory consistency: Many controlled drugs must be used in prescribed forms; allowing free smoking would conflict with other drug regulations and public law.
Liability and enforcement: Authorities prefer clear lines — “no smoking” is simpler to enforce than case-by-case judgments of medical use.

What You Can Do — and How to Use Safely in Public

Because smoking is largely off the table under UK law, patients (or prospective patients) must rely on alternative, legal routes to take their medication safely and lawfully in public.

Use the method prescribed

When you are prescribed CBMPs, your clinician will specify the allowed formulation and route. Common forms include:

Dry flower (“flos”) to be delivered via a medical-grade vaporiser (not combustion)
Oils, tinctures or sublingual drops
Cartridges, capsules, or other non-smoking formulations

Using them only in the way prescribed is essential for legality, safety, and maintaining your prescription. (The Medical Cannabis Clinicians Society)

Choosing where to use it

If your prescribed form is vaporisation (dry herb) or a vape cartridge, you may be able to use it in public spaces where vaping is allowed (if any). That said:

Many indoor public spaces (pubs, cafés, shopping centres) ban vaping or smoking altogether.
Outdoor public areas usually have fewer restrictions, but it depends on local rules.
Some venues might refuse entry if you’re carrying or using cannabis medication — even if you have a prescription. Patients’ advocacy groups report instances of venue staff being uninformed.

Carrying documentation

If you are carrying prescribed medical cannabis outside your home:

Keep it in its original container (pharmacy packaging).
Carry photo ID matching your prescription.
Carry a copy of your prescription or clinic letter (physical or digital).
If stopped by police, remain calm and comply. You are under no general duty to volunteer your prescription, but if they suspect impairment or possession, showing the documentation may help clarify your legal patient status.

Public transport & venues

Before attempting to consume your dose while on public transport, plane, train or in other public venues:

Check policies: some services prohibit vaping or have rules about controlled medications.
Inform security or staff if needed: having your prescription documentation may ease misunderstanding.
Prefer discreet, non-odorous forms (oils, tinctures) over inhaled forms where possible, especially in tightly enclosed public spaces.

Why Does This Matter — And What Patients Experience

Barriers to access & confusion

Even though medical cannabis was enabled legally in 2018, many patients find it extremely difficult to access via the NHS. (PMC) Some choose private routes, but then face regulatory uncertainty about how to travel or be out in public.

This patchwork of rules and perceptions means patients sometimes experience stigma, refusal of entry at venues, or lack of clarity when questioned by police or security.

Advocacy & reasonable adjustments

Some local authorities are beginning to recognise medically assisted cannabis use as a disability accommodation issue. For example, Salford Council passed a motion to protect the rights of medical cannabis patients in public spaces, under the Equality Act.

At CPGUK, we believe stronger, clearer guidance and awareness is needed so that patients are not penalised or discriminated against for using a lawful medicine.

FAQ

Can I legally smoke medical cannabis in public in the UK?
No. It is illegal to smoke medical cannabis in public in the UK, even with a prescription. Under the Misuse of Drugs Act 1971, smoking cannabis is considered a criminal offence. Patients may only consume their prescribed medication in permitted forms such as oils, capsules, or vaporised flower.
(Source: legislation.gov.uk)

Why is smoking medical cannabis illegal even with a prescription?
Smoking is not an approved medical route in the UK because combustion releases harmful toxins and makes dosage control difficult. The NHS and Home Office only recognise prescribed non-combustion methods such as vaporising or using oral oils.
(Source: NHS)

Can I use my prescribed medical cannabis in public?
Yes, but only in the way your doctor prescribed it. If your prescription allows vaporised cannabis flower, you may vape it only in areas where vaping is permitted. Always carry your prescription label, clinic letter, and photo ID to verify lawful use.

Can I smoke medical cannabis at home in the UK?
No. Smoking medical cannabis at home is still prohibited by UK law. However, patients may legally vaporise prescribed cannabis flower or use oils in private settings in accordance with their prescription.
(Source: Home Office)

Where can I legally vape medical cannabis in public?
You can vape medical cannabis in outdoor areas where vaping is allowed. Vaping is banned on public transport, in workplaces, pubs, cafés, and enclosed public spaces under the Health Act 2006.
(Source: BBC)

What should I do if the police stop me with medical cannabis?
Stay calm and provide documentation. Show your prescription, photo ID, and ensure your medication remains in its original container. This demonstrates you are a registered medical cannabis patient and prevents confiscation or legal misunderstanding.

Does UK medical cannabis make you high?
Not typically. Most UK prescriptions are CBD-dominant with low or no THC, meaning they do not cause intoxication. Where THC is prescribed, doses are medically controlled to minimise psychoactive effects.
(Source: NHS)

Can the police confiscate my prescribed cannabis?
Yes, if they suspect unlawful possession or misuse. To avoid this, always carry your prescription and ID, and keep your medication in its original packaging clearly marked by a UK pharmacy.

Is there a legal THC limit in the UK?
Yes, but only for driving. The legal limit is 2 micrograms of THC per litre of blood, but driving while impaired remains an offence — even with a medical prescription.
(Source: GOV.UK)

Why does CPGUK advocate for patient rights?
Because patients still face stigma, confusion, and inconsistent enforcement around medical cannabis laws. CPGUK helps educate patients, raise awareness among law enforcement, and campaign for fairer access to prescribed cannabis-based treatments.
(Source: CPGUK.org)

Key points:

Smoking medical cannabis is illegal in public and private spaces.
Vaporising or using oils is legal when prescribed and used correctly.
Always carry proof of prescription and photo ID in public.
Driving while impaired remains an offence even with a prescription.
Education and awareness are key to protecting patient rights.