Drug driving
Drug driving covers two offences: driving while unfit through drugs (section 4) and driving with a specified controlled drug in the blood above a set limit (section 5A). Scotland has set its own limits, in force since 21 October 2019, with very low limits for illegal drugs such as cannabis and cocaine.
Law checked as at 25 September 2026. Legal information only, not legal advice, and not a prediction of any sentence.
At a glance
| Also known as | Driving with a specified drug above the limit, Driving while unfit through drugs, Drugged driving |
|---|---|
| The law | Road Traffic Act 1988, section 5A (and section 4) |
| Where it is tried | a summary-only offence, prosecuted under summary procedure, usually in the sheriff court. It cannot be tried before a jury. |
| Maximum penalty | Driving or attempting to drive (section 4 or 5A): up to 6 months' imprisonment and/or a fine of up to £5,000, with obligatory disqualification of at least 12 months (at least 3 years for a second drink or drug driving conviction within 10 years). Being in charge: up to 3 months' imprisonment and/or a fine of up to £2,500, with 10 penalty points or discretionary disqualification. In Scotland the prosecutor can also seek forfeiture of the vehicle. |
Maximum penalties are the most a court can impose for the worst cases. Most sentences are far lower, and the actual sentence depends on the facts, any guilty plea and the court's assessment.
What the prosecution must prove
- The accused drove, attempted to drive or was in charge of a motor vehicle on a road or other public place.
- For section 5A: a specified controlled drug was in their body at a level in the blood or urine above the limit set by the Drug Driving (Specified Limits) (Scotland) Regulations 2019.
- For section 4: the accused was unfit to drive through drink or drugs, meaning their ability to drive properly was impaired; no set limit applies.
- The blood or urine specimen was required, taken and analysed following the correct statutory procedure.
Defences and common issues
- Medical defence (section 5A(3)): the drug was lawfully prescribed or supplied and taken in line with the directions of the prescriber and the manufacturer, and the accused did not ignore advice about how long to wait before driving.
- Procedural challenge to how the blood specimen was required, taken or analysed.
- The accused was not driving or on a road or other public place, or, for being in charge, there was no likelihood of driving while over the limit.
- For section 4: disputing that the accused's ability to drive was actually impaired.
Frequently asked questions
What are the drug driving limits in Scotland?
The Drug Driving (Specified Limits) (Scotland) Regulations 2019 set limits in microgrammes per litre of blood. For illegal drugs they are very low: cannabis (THC) 2, cocaine 10, ecstasy (MDMA) 10, ketamine 20, LSD 1, methylamphetamine 10 and heroin (6-monoacetylmorphine) 5. Some medicines have higher limits, including diazepam 550, methadone 500, morphine 80, amphetamine 250 and temazepam 1000. Being above the limit is an offence even if your driving was not affected.
Can I drive in Scotland if I take prescribed medication?
Often yes, but you must not be impaired. For drugs covered by the set limits, section 5A of the Road Traffic Act 1988 gives a medical defence if the drug was prescribed or supplied to you for medical purposes and you took it as directed by the prescriber and the manufacturer's instructions. The defence is lost if you ignored advice about how long to wait before driving. Separately, driving while actually unfit through any drug, including prescribed medicine, is an offence under section 4 whatever the level.
How do police test for drugs at the roadside in Scotland?
Police can require a preliminary drug test, usually a mouth swab that can detect cannabis and cocaine, and a preliminary impairment test involving simple physical tasks. If the result or your driving gives grounds for suspicion, you can be arrested and asked to provide a blood specimen at a police station or hospital for laboratory analysis. Failing to cooperate with these tests without reasonable excuse is itself an offence. You have the right to free legal advice from a solicitor if you are arrested.
Can I be convicted of drug driving for cannabis I used days ago?
Possibly. The section 5A offence depends on the level of THC, the active ingredient of cannabis, in your blood when you were driving, not on whether you felt affected. The Scottish limit is 2 microgrammes per litre of blood, which is very low. How long THC stays above that level varies from person to person and with how much and how often cannabis is used. Some products sold as CBD can also contain THC. Only a laboratory blood analysis can show the actual level.
Is drug driving punished the same as drink driving in Scotland?
Yes, the maximum penalties are the same. Driving or attempting to drive while unfit through drugs, or above a specified drug limit, carries up to 6 months' imprisonment, a fine of up to £5,000 and an obligatory ban of at least 12 months. A second drink or drug driving conviction within 10 years brings a minimum ban of 3 years. The conviction stays on your driving record for 11 years, and the Procurator Fiscal can ask the court to forfeit the vehicle.
Work out your penalty points, totting-up and ban risk.
Penalty points calculator →Official sources
Primary sources and official guidance on this topic, for anyone who wants to read the underlying rules directly.
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