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UK Medical Cannabis Law: Driving, DVLA & Legal Rights Guide

Section 3: Careless, and inconsiderate, driving

If a person drives a mechanically propelled vehicle on a road or other public place without due care and attention, or without reasonable consideration for other persons using the road or place, he is guilty of an offence.

Section 3ZA: Meaning of careless, or inconsiderate, driving

(1) This section has effect for the purposes of sections 2B and 3 above and section 3A below.

(2) A person is to be regarded as driving without due care and attention if (and only if) the way he drives falls below what would be expected of a competent and careful driver.

(3) In determining for the purposes of subsection (2) above what would be expected of a careful and competent driver in a particular case, regard shall be had not only to the circumstances of which he could be expected to be aware but also to any circumstances shown to have been within the knowledge of the accused.

(4) A person is to be regarded as driving without reasonable consideration for other persons only if those persons are inconvenienced by his driving.

Section 3ZB: Causing death by driving: unlicensed, disqualified or uninsured drivers

A person is guilty of an offence under this section if he causes the death of another person by driving a motor vehicle on a road and, at the time when he is driving, the circumstances are such that he is committing an offence under—

(a) section 87(1) of this Act (driving otherwise than in accordance with a licence),
(b) section 103(1)(b) of this Act (driving while disqualified), or
(c) section 143 of this Act (using motor vehicle while uninsured or unsecured against third party risks).

Section 3A: Causing death by careless driving when under influence of drink or drugs

(1) If a person causes the death of another person by driving a mechanically propelled vehicle on a road or other public place without due care and attention, or without reasonable consideration for other persons using the road or place, and—

(a) he is, at the time when he is driving, unfit to drive through drink or drugs, or
(b) he has consumed so much alcohol that the proportion of it in his breath, blood or urine at that time exceeds the prescribed limit, or
(ba) he has in his body a specified controlled drug and the proportion of it in his blood or urine at that time exceeds the specified limit for that drug, or
(c) he is, within 18 hours after that time, required to provide a specimen in pursuance of section 7 of this Act, but without reasonable excuse fails to provide it, or
(d) he is required by a constable to give his permission for a laboratory test of a specimen of blood taken from him under section 7A of this Act, but without reasonable excuse fails to do so,

he is guilty of an offence.

(2) For the purposes of this section a person shall be taken to be unfit to drive at any time when his ability to drive properly is impaired.

Section 4: Driving, or being in charge, when under influence of drink or drugs

(1) A person who, when driving or attempting to drive a mechanically propelled vehicle on a road or other public place, is unfit to drive through drink or drugs is guilty of an offence.

(2) Without prejudice to subsection (1) above, a person who, when in charge of a mechanically propelled vehicle which is on a road or other public place, is unfit to drive through drink or drugs is guilty of an offence.

(3) For the purposes of subsection (2) above, a person shall be deemed not to have been in charge of a mechanically propelled vehicle if he proves that at the material time the circumstances were such that there was no likelihood of his driving it so long as he remained unfit to drive through drink or drugs.

(4) The court may, in determining whether there was such a likelihood as is mentioned in subsection (3) above, disregard any injury to him and any damage to the vehicle.

(5) For the purposes of this section, a person shall be taken to be unfit to drive if his ability to drive properly is for the time being impaired.

Section 5: Driving or being in charge of a motor vehicle with alcohol concentration above prescribed limit

(1) If a person—

(a) drives or attempts to drive a motor vehicle on a road or other public place, or
(b) is in charge of a motor vehicle on a road or other public place,

after consuming so much alcohol that the proportion of it in his breath, blood or urine exceeds the prescribed limit he is guilty of an offence.

(2) It is a defence for a person charged with an offence under subsection (1)(b) above to prove that at the time he is alleged to have committed the offence the circumstances were such that there was no likelihood of his driving the vehicle whilst the proportion of alcohol in his breath, blood or urine remained likely to exceed the prescribed limit.

Section 5A: Driving or being in charge of a motor vehicle with concentration of specified controlled drug above specified limit

(1) This section applies where a person (“D”)—

(a) drives or attempts to drive a motor vehicle on a road or other public place, or
(b) is in charge of a motor vehicle on a road or other public place,

and there is in D's body a specified controlled drug.

(2) D is guilty of an offence if the proportion of the drug in D's blood or urine exceeds the specified limit for that drug.

The Medical Defence (Section 5A(3))

(3) It is a defence for a person (“D”) charged with an offence under this section to show that—

(a) the specified controlled drug had been prescribed or supplied to D for medical or dental purposes,
(b) D took the drug in accordance with any directions given by the person by whom the drug was prescribed or supplied, and with any accompanying instructions... given by the manufacturer or distributor of the drug, and
(c) D's possession of the drug immediately before taking it was not unlawful under section 5(1) of the Misuse of Drugs Act 1971...

(4) The defence in subsection (3) is not available if D's actions were—

(a) contrary to any advice... about the amount of time that should elapse between taking the drug and driving a motor vehicle, or
(b) contrary to any accompanying instructions about that matter...

Section 6: Power to administer preliminary tests

(1) If any of subsections (2) to (5) applies a constable may require a person to co-operate with any one or more preliminary tests administered to the person by that constable or another constable.

(2) This subsection applies if a constable reasonably suspects that the person—

(a) is driving, is attempting to drive or is in charge of a motor vehicle on a road or other public place, and
(b) has alcohol or a drug in his body or is under the influence of a drug.

(6) A person commits an offence if without reasonable excuse he fails to co-operate with a preliminary test in pursuance of a requirement imposed under this section.

Section 6A: Preliminary breath test

(1) A preliminary breath test is a procedure whereby the person to whom the test is administered provides a specimen of breath to be used for the purpose of obtaining... an indication whether the proportion of alcohol in the person’s breath or blood is likely to exceed the prescribed limit.

Section 6B: Preliminary impairment test

(1) A preliminary impairment test is a procedure whereby the constable administering the test—

(a) observes the person to whom the test is administered in his performance of tasks specified by the constable, and
(b) makes such other observations of the person’s physical state as the constable thinks expedient.

Section 6C: Preliminary drug test

(1) A preliminary drug test is a procedure by which a specimen of sweat or saliva is—

(a) obtained, and
(b) used for the purpose of obtaining... an indication whether the person to whom the test is administered has a drug in his body...

Section 6D: Arrest

(1) A constable may arrest a person without warrant if as a result of a preliminary breath test or preliminary drug test the constable reasonably suspects that—

(a) the proportion of alcohol in the person's breath or blood exceeds the prescribed limit, or
(b) the person has a specified controlled drug in his body and the proportion of it in the person's blood or urine exceeds the specified limit for that drug.

Patient Protection: Key Takeaways

Your Statutory Defence

Under Section 5A(3), you have a statutory defence against being "over the limit" for THC if:

The cannabis is lawfully prescribed by a specialist.
You are following the prescriber's instructions.
You are NOT impaired (Section 4 offence has no defence).

How to Achieve the Best Outcome

1.Carry Evidence: Always have your latest paper prescription copy and photo ID with you while driving.
2.Original Packaging: Keep medication in its original pharmacy-labelled container to prove legality.
3.If Stopped: Calmly inform the officer you are a medical cannabis patient. If a roadside swab is positive, do not panic. You may be arrested for a blood test—this is often procedural. Comply fully; your defence applies after this stage.

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