Driving under the influence of drink or drugs
More commonly known as drink driving, or drug driving.
It is an offence to drive, or attempt to drive, or to be in charge of a vehicle on a road or other public place, when your ability to drive properly is impaired through drink or drugs.
You can be charged with driving under the influence of drink or drugs if your ability to drive is considered to have been impaired by drink or drugs, including also prescription drugs. In the case of alcohol, you can be charged even if you "passed" a breath test.
"Drugs" in this context is not limited to illicit substances. Any intoxicant can be regarded as "drugs" for the purposes of this offence, including properly prescribed medicines.
The prosecution may prove that your ability to drive properly was impaired by putting forward opinion evidence. The opinion of a lay person such as a police officer can suffice for this purpose but it is usual for the prosecution to rely on the evidence of an expert witness - usually the police doctor who is likely to have examined the accused at the police station.
This offence is charged where for any reason the sample evidence required to support a charge of driving or being in charge with excess alcohol in breath, blood or urine is unavailable. The offence can be charged even when you have "passed" a breath test if the Police consider that your ability to drive is impaired.
The defences available are similar to those available in cases of driving with excess alcohol.
Penalties for driving under the influence
The penalties for driving or attempting to drive under the influence are similar to those for excess alcohol offences: in particular, a minimum disqualification of 12 months applies, unless "special reasons" are found. The penalties for being in charge while under the influence are similar to those for being in charge with excess alcohol.