It is illegal to drive or attempt to drive a vehicle with specific levels of drugs in your blood system. To be convicted, it is necessary for the prosecution to prove that:

  • A person was driving or attempting to drive a motor vehicle; and
  • They have in their body a specified controlled drug and the proportion is over the prescribed limit

Unfortunately, some drugs remain in a person’s body for considerable periods of time after they have consumed them. This is particularly true of cannabis (Delta-9-Tetrahydrocannabinol). Research has shown that a first-time user of cannabis can test positive for up to 4 days after last taking the drug. A very heavy user of cannabis could test positive for up to 2 months after last taking it.

Controlled Drugs and their Specified Limits

Controlled drug Limit (microgrammes per litre of blood)
Benzoylecgonine 50
Clonazepam 50
Cocaine 10
Delta-9-Tetrahydrocannabinol 2
Diazepam 550
Flunitrazepam 300
Ketamine 20
Lorazepam 100
Lysergic Acid Diethylamide 1
Methadone 500
Methylamphetamine 10
Methylenedioxymethamphetamine 10
6-Monoacetylmorphine 5
Morphine 80
Oxazepam 300
Temazepam 1000


Guidance has been issued by the Sentencing Council. If you are convicted of this offence you could face a fine, a community order or imprisonment. The maximum penalty is 6 months imprisonment. If convicted, the Court must disqualify for at least 12 months. The minimum period of disqualification is increased to 3 years if the driver has previously been convicted of a relevant offence in the last 10 years.

Given the range of possible sentences it is important to get expert legal advice and representation at an early stage from experienced motoring offence solicitors.


There are defences available in relation to this offence and it is important to get legal advice at an early stage.

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