Drug Driving Information
27th of August, 2026
Drug driving means operating a vehicle while under the influence of drugs, whether they are:
- Illegal drugs such as cannabis, cocaine, heroin, ketamine or MDMA.
- Legal drugs, including prescribed medication and over-the-counter medicines that can impair driving ability.
Drug driving is a serious criminal offence and presents significant risks to drivers, passengers and other road users.
The Law
There are two main drug driving offences:
- Driving whilst unfit through drugs.
- Driving with a specified controlled drug above the legal limit in your system.
Across England, Scotland and Wales, it is illegal to:
- Drive while impaired by any drug.
- Drive with a specified controlled drug in your blood above the legal limit.
Understanding Drug Limits
Many motorists find drug driving limits confusing. In reality, it is impossible to determine exactly how much of a drug can be taken before exceeding the legal limit, as this depends on a range of factors, including:
- Age
- Gender
- Weight and body composition
- Dosage taken
- Frequency of use
- Metabolism
For illegal drugs, the limits are set at near zero-tolerance levels, meaning even a very small amount may place someone over the legal limit.
Prescription Medication
Legal medications can still affect your ability to drive safely. For many prescribed drugs, the specified limits are generally set to allow normal therapeutic use when taken as directed.
Where medication has been:
- Prescribed by a healthcare professional
- Taken exactly as directed
A statutory medical defence may be available, provided the medication was prescribed or supplied for medical purposes, taken in line with medical advice and instructions, and the driver was not impaired.
Always check the guidance supplied with your medication and speak to your doctor or pharmacist if you are unsure whether it is safe to drive.
How Long Do Drugs Stay in Your System?
There is no definitive answer. Detection times vary considerably depending on the individual and the substance used.
Approximate detection periods include:
- Cannabis: 2 to 3 days (up to 2 months for regular users)
- Cocaine: Around 12 hours to 3 days
- MDMA: 1 to 4 days
- Heroin: 2 to 5 days
- Ketamine: 2 to 4 days
- LSD: 1 to 3 days
- Crystal Meth: 1 to 4 days
These times are estimates only and should not be relied upon when deciding whether it is safe or legal to drive.
What Happens If You're Caught?
If a blood sample shows a specified controlled drug above the legal limit, you are likely to be charged with drug driving and required to attend court.
A conviction can result in:
- A minimum 12-month driving disqualification
- An unlimited fine
- Up to six months' imprisonment or a community order
- A criminal record
- Travel restrictions to certain countries, including the USA
- An endorsement remaining on your driving licence for 11 years
- Significant increases in motor insurance premiums
Impact on Employment
A drug driving conviction can have long-term consequences for your career. Employers, particularly where driving forms part of a role, may review driving records and convictions. Certain professions and regulatory bodies may also require disclosure of criminal convictions, which could affect employment opportunities.
Think You Won't Get Caught? Think Again
Last year, Lancashire Constabulary conducted thousands of roadside stops, breath tests and drug tests, resulting in a significant number of positive results and arrests for drink and drug driving offences.
Drug driving remains a key road safety enforcement priority, and officers have the power to carry out roadside drug screening where they suspect a driver has taken drugs.
If you have taken drugs, whether illegal or prescribed, and are unsure whether they could affect your driving, don't take the risk.
Think before you drive. If you drive under the influence of drugs, you risk being stopped, tested, arrested and convicted.