It’s illegal to drive if either:

  • you’re unfit to do so because you’re on legal or illegal drugs
  • you have certain levels of illegal drugs in your blood (even if they haven’t affected your driving)
Legal drugs are prescription or over-the-counter medicines. If you’re taking them and not sure if you should drive, talk to your doctor, pharmacist or healthcare professional.

The police can stop you and make you do a ‘field impairment assessment’ if they think you’re on drugs. This is a series of tests, eg asking you to walk in a straight line. They can also use a roadside drug kit to screen for cannabis and cocaine.

If they think you’re unfit to drive because of taking drugs, you’ll be arrested and will have to take a blood or urine test at a police station.

You could be charged with a crime if the test shows you’ve taken drugs.

Police forces have access to new screening equipment to test suspected drug drivers. Officers can screen drivers for cannabis and cocaine at the roadside. They will be able to test for these and other drugs including ecstasy, LSD, ketamine and heroin at a police station, even if a driver passes the roadside check. New devices that can test for a greater number of drugs at the roadside will be developed in the future.

The law states that it is an offence to drive with certain drugs above specified blood levels in the body, whether your driving is impaired or not. This will make it easier for the police to tackle drug drivers.

The law sets limits at very low levels for eight drugs commonly associated with illegal drug use, such as cannabis and cocaine, to tackle illegal drug use and driving.


Prescription medicines

It’s illegal in England and Wales to drive with legal drugs in your blood if they impair your driving.

It’s an offence to drive if you have over the specified limits of certain drugs in your blood and you haven’t been prescribed them.

The law includes eight drugs commonly associated with medicinal use, that are sometimes abused, that have been set at higher limits based on the available evidence of the road safety risk and to reflect their use as medicines.

Talk to your doctor about whether you should drive if you’ve been prescribed any of the following drugs:

  • Morphine used to treat pain - opiate/opioid based medication will metabolise (chemically change) into morphine and show in a blood result, e.g. codeine, tramadol or fentanyl
  • Clonazepam, diazepam, flunitrazepam, lorazepam, oxazepam, temazepam used to treat anxiety or inability to sleep
  • Methadone used to treat drug addiction
  • Amphetamine, e.g. dexamphetamine or selegiline, used to treat attention deficit hyperactivity disorder (ADHD) and Parkinson's disease is also planned to be included within the offence in the longer term.

You can drive after taking these drugs if:

  • you’ve been prescribed them and followed advice on how to take them by a healthcare professional, and
  • they aren’t causing you to be unfit to drive but you must be within the specified limits
You could be prosecuted if you drive with certain levels of these drugs in your body and you haven’t been prescribed them.
The majority of patients that are fit to drive and are taking medicines as directed are unlikely to be above the specified limit and therefore would not be committing an offence.

Even if you are above the specified limit but your driving is not impaired and you are taking your medicine in accordance with the advice of a healthcare professional and/or as printed in the accompanying leaflet you will also be within the law.

The law doesn’t cover Northern Ireland and Scotland but you could still be arrested if you’re unfit to drive.


What should I do if I need to take any of the specified medicines?

Certain medicines may affect your ability to drive.

  • Keep taking your medicines as prescribed.
  • Check the leaflet that comes with your medicines until you know how they affect you.
  • Do not drive after taking your medicine until you know how it affects you.
  • Do not drive if you feel drowsy dizzy, unable to concentrate or make decisions or if you have blurred or double vision.
  • If you are taking your medicine in accordance with the advice of a healthcare professional and/or as printed in the accompanying leaflet and your driving is not impaired plus you are within the specified levels, then you are not breaking the law.
If you are unsure how the change will affect you, talk to your doctor or a member of the pharmacy team.



Penalties for drug driving

If the test detects any relevant drugs, or they suspect you to be under the influence of drugs, the type and level of the drugs in your body can be confirmed by a blood test at the police station. There is a medical defence that can be raised for the offence if drivers are taking medication as directed and found to be over the limit but not impaired. Drivers taking relevant medicines may choose to have evidence with them when driving to indicate that they have been legitimately supplied and minimise inconvenience. The medical defence states that you are not guilty if:

  • the medicine was prescribed, supplied, or sold to you to treat a medical or dental problem, and
  • you took the medicine according to the instructions given by the prescriber, a pharmacist or a member of the pharmacy team or the information provided with the medicine.

If you’re convicted of drug driving you’ll get:

  • a minimum 1 year driving ban
  • an unlimited fine
  • up to 6 months in prison
  • a criminal record

Your driving licence will also show you’ve been convicted for drug driving. This will last for 11 years.

The penalty for causing death by dangerous driving under the influence of drugs is a prison sentence of up to 14 years.


Other problems you could face

A conviction for drug driving also means:

  • your car insurance costs will increase significantly
  • if you drive for work, your employer will see your conviction on your licence
  • you may have trouble travelling to countries like the USA


It will remain an offence to drive while your ability is impaired and, if in doubt, you should not drive.
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