Drug driving
Drug driving under section 5A means driving, attempting to drive or being in charge of a motor vehicle with certain controlled drugs in your blood or urine above set limits. It can be committed even if your driving was not affected. Driving while unfit through drugs is a separate offence under section 4.
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, Drug-drive, Driving while unfit through drugs |
|---|---|
| The law | Road Traffic Act 1988, section 5A |
| Where it is tried | summary only. Section 5A drug driving is dealt with in the magistrates' court. |
| Maximum penalty | Driving or attempting to drive: 6 months' imprisonment and/or an unlimited fine, plus an obligatory ban of at least 12 months (at least 3 years for a repeat drink or drug driving offence within 10 years). Being in charge: 3 months' imprisonment and/or a fine of up to £2,500 (level 4), with 10 penalty points or a discretionary ban. The same maximums apply to driving, or being in charge, while unfit through drugs under section 4. |
| Sentencing guideline | Driving or Attempting to Drive with a specified drug above the specified limit |
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 defendant drove, attempted to drive, or was in charge of a motor vehicle on a road or other public place.
- There was a specified controlled drug in their body, such as cannabis (THC), cocaine or certain prescription medicines listed in regulations.
- The proportion of that drug in their blood or urine exceeded the specified limit for it, proved by laboratory analysis.
- The prosecution does not need to prove that the person's driving was impaired; the level alone is enough.
Defences and common issues
- Medical defence: the drug was prescribed or supplied for medical or dental purposes and taken in line with the directions and the manufacturer's instructions, including advice about how long to wait before driving (s.5A(3)-(4)).
- For the in-charge offence, it is a defence to prove there was no likelihood of driving while still over the limit (s.5A(6)).
- Challenges to how the blood or urine sample was taken, stored, labelled or analysed.
- Special reasons, such as unknowingly consuming a drug, are not a defence but may allow the court not to impose a ban.
Frequently asked questions
Can I be convicted of drug driving if my driving was fine?
Yes. Under section 5A of the Road Traffic Act 1988 it is an offence to drive with certain controlled drugs in your blood above a specified limit, whether or not your driving was affected. For illegal drugs such as cannabis and cocaine the limits are set very low, so even use some time before driving can lead to a positive result. There is a separate offence under section 4 of driving while unfit through drink or drugs, which does require evidence that your ability to drive was impaired.
Is it illegal to drive on prescription medication?
Not automatically. Some medicines, including diazepam, morphine and methadone, have specified limits, but you have a defence if the drug was prescribed or supplied to you for medical purposes and you took it as directed, including any advice about waiting before driving. The defence does not help if you were actually unfit to drive, because driving while impaired by any drug is still an offence under section 4. GOV.UK advises talking to your doctor or pharmacist if you are unsure.
How do police test for drug driving?
Police can carry out a roadside field impairment assessment, such as asking you to walk in a straight line, and can use a roadside kit to screen saliva for cannabis and cocaine. If they suspect an offence, you can be arrested and asked for a blood sample, or in some cases urine, at the police station. Failing to provide a specimen without a reasonable excuse is itself an offence with similar penalties. You have the right to free legal advice at the police station.
What is the difference between drug driving and driving while unfit?
Section 5A drug driving is based purely on the level of a specified drug in your blood or urine, so no impairment needs to be shown. Driving while unfit under section 4 applies to any drug, legal or illegal, and to alcohol, but the prosecution must prove your ability to drive was impaired, often through a doctor's examination and police observations. Both carry a maximum of 6 months' imprisonment, an unlimited fine and an obligatory ban of at least 12 months when you were driving or attempting to drive.
Will a drug driving conviction show on my licence and record?
Yes. A conviction for drug driving is a criminal conviction and is also endorsed on your driving licence. A driving or attempting to drive conviction brings an obligatory ban of at least 12 months, and a second drink or drug driving conviction within 10 years brings at least 3 years. The endorsement stays on your driving record for 11 years. Motor insurers will usually ask about it, and some jobs and countries may require you to disclose it.
Work out your penalty points, totting-up and ban risk.
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Primary sources and official guidance on this topic, for anyone who wants to read the underlying rules directly.
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