Drug Driving Legal Limits

The UK's policy on drug driving is zero tolerance. This means that the legal limits are extremely low. Even passive exposure could put you over the limit. 

We can help you;

  • Understand the legal limits 
  • Avoid testing positive 
  • Learn about metabolites

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What are the drug driving limits?

Unlike drink driving offences, it’s difficult – if not impossible – to work out what the new drug driving limits actually mean, making it much easier to break the law. Please remember that you can still be found guilty of drug driving even if you did not intend to be over the limit - and even if you were not impaired. We may be able to take advantage of these confusing limits to help win your case.

The legal drug driving limits are as follows:

Illegal Drug Legal Limit (Blood)
Benzoylecgonine 50µg/L
Cocaine 10µg/L
Delta – 9 -Tetrahydrocannibinol (Cannabis) 2µg/L
Ketamine 20µg/L
Lysergic Acid Diethylamide 1µg/L
Methylamphetamine 10µg/L
MDMA 10µg/L
6 – Monoacetylmorphine (Heroin) 10µg/L

(‘µg/L’ means ‘micrograms per litre of blood)

Prescription Drugs 

Prescription Drug Legal Limit (Blood)
Amphetamine 250µg/L
Clonazepam 50µg/L
Diazepam 550µg/L
Flunitrazepam 300µg/L
Lorazepam 100µg/L
Methadone 500µg/L
Morphine 80µg/L
Oxazepam 300µg/L
Temazepam 1,000µg/L


In drug driving cases the legal limits are relatively meaningless.

This is because guidance issued by the Magistrates’ Courts Sentencing Council in November 2016 advised all magistrates to impose a 12 month driving disqualification for a first time offender, even if the result was two or three times the legal limit. If the offender has a previous drink or drug driving conviction within the last ten-years, the minimum disqualification will be three years. If the magistrates feel as though the circumstances are more serious due to aggravating factors (such as a collision, poor driving etc…) then this will increase the disqualification period.

Of course, if you avoid a conviction then you cannot be disqualified. To chat in confidence about your case, fill in the contact form below and a member of our team will be in touch.

Please don’t make the mistake of accepting the accuracy of the blood test results without checking the prosecution’s analytical data. This data, often in excess of 300 pages, contains;

  • Calibration checks
  • Quality control & quality assurance
  • Sample preservation
  • Storage
  • Method of analysis

Drug Driving Technical Defences

Some labs get it wrong. No analytical method is 100% accurate.