Central Chambers Law
Drug Driving (Driving Whilst Unfit Through Drugs)

An allegation of drug driving is a serious criminal offence with severe consequences. It alleges that you were driving, attempting to drive, or in charge of a vehicle while either unfit through drugs or with a concentration of a specified drug in your system above the legal limit. A conviction results in a mandatory driving disqualification of at least 12 months, a criminal record, and the potential for a prison sentence. The law is complex and the police procedures are technical, making immediate, specialist legal representation essential to protect your licence and your liberty.
At Central Chambers Law, our senior legal consultants are experts in defending all motoring offences, including the technicalities of drug driving cases. We possess an in-depth knowledge of the legislation, the scientific evidence involved, and the procedural requirements the police must follow. Our function is to provide a formidable, strategic defence that forensically examines every aspect of the prosecution's case. We are specialists equipped to challenge the evidence and fight for the best possible outcome for you.
Understanding the Offence: What is Drug Driving?
The law on drug driving is primarily governed by the Road Traffic Act 1988. There are two distinct offences:
- Driving whilst unfit through drugs (Section 4): This is the older offence. A person is guilty if they drive or are in charge of a vehicle while their ability to drive properly is impaired by a drug (whether legal or illegal). The prosecution must prove impairment.
- Driving with a concentration of a specified drug above the specified limit (Section 5A): This is a newer, stricter offence introduced in 2015. It makes it illegal to drive with certain levels of 17 specified drugs in your blood, regardless of whether your driving was impaired. This is similar to the drink driving limit, making it much easier for the prosecution to secure a conviction.
The Section 5A offence covers eight illegal drugs, including cannabis and cocaine, and nine commonly prescribed medications. This means you can be prosecuted even if you are taking medication as prescribed by your doctor.
The Key Elements of the Offence
To secure a conviction, the prosecution's burden of proof depends on the specific charge.
For Driving whilst unfit (Section 4), they must prove:
- You were driving or in charge of a vehicle on a public road or place.
- You were unfit to drive.
- The unfitness was due to a drug.
For Driving over the specified limit (Section 5A), they must prove:
- You were driving or attempting to drive a vehicle on a public road or place.
- A specified controlled drug was present in your body.
- The level of that drug in your blood was above the legal limit for that drug.
For the Section 5A offence, there is no need to prove bad driving or impairment. The case rests entirely on the result of a blood test.
How Drug Driving Cases are Investigated
The procedure for a drug driving investigation is strict and must be followed correctly by the police. Any error can provide the basis for a defence.
The typical process is:
- Roadside Stop and Test: Police can stop you if they suspect you are under the influence of drugs. They can administer a preliminary roadside drug test (a "drugalyser") which screens for cannabis and cocaine. They can also conduct a Field Impairment Test (FIT) to assess your coordination.
- Arrest: If you fail the roadside test, or if the police officer has a reasonable suspicion you are impaired by drugs, you will be arrested and taken to a police station.
- Evidential Blood or Urine Sample: At the police station, you will be required to provide an evidential sample of blood or, in some cases, urine. This sample is then sent to a laboratory for forensic analysis to determine the precise concentration of any drugs.
- Charge: If the analysis confirms you were over the legal limit or provides evidence of impairment, you will be charged and required to attend Magistrates' Court.
Why Central Chambers Law Provides the Definitive Defence
Defending a drug driving allegation is a highly technical and specialised area of law. It involves challenging police procedure and complex scientific evidence. A general criminal lawyer may lack the specific expertise required to identify the crucial flaws in a prosecution case.
Clients trust Central Chambers Law because we are experts in motoring law. Our reputation is built on our ability to meticulously scrutinise every detail of the evidence and procedure. Our strategic approach involves:
- Forensic Review of Police Procedure: We examine every step of the investigation for errors. Were you stopped lawfully? Were the correct procedures and warnings followed at the roadside and at the police station? Was the blood sample taken, stored, and transported correctly? A single procedural failure can be fatal to the prosecution's case.
- Challenging the Scientific Evidence: We do not simply accept the lab report. We are experts in analysing the forensic data, including the laboratory's own testing and calibration records. We can instruct our own independent toxicologists to review the findings and challenge the reliability of the blood test result.
- Advancing Statutory Defences: For the Section 5A offence, there is a specific statutory defence if you were taking a prescribed medication in accordance with medical advice. We are experts in gathering the necessary evidence and presenting this defence effectively.
- Contesting Impairment: In Section 4 cases, we vigorously challenge the police officer's opinion that your driving was impaired. We scrutinise the Field Impairment Test evidence and any other observations to demonstrate that you were fit to drive.
Our focused expertise means we are perfectly equipped to provide the technical, intelligent defence necessary when your driving licence is on the line.
Consequences of a Conviction
The penalties for drug driving are severe and are on par with those for drink driving.
- Mandatory Driving Disqualification: A conviction leads to a minimum driving ban of 12 months (or 3 years for a second offence within 10 years).
- Unlimited Fine and/or Prison: The offence carries an unlimited fine and a maximum penalty of 6 months' imprisonment.
- Criminal Record: A conviction will result in a criminal record which can impact your employment, travel, and insurance for years to come.
Protect Your Licence with an Expert Defence
A drug driving allegation is a direct and serious threat to your ability to drive. The law is complex, and the evidence is highly scientific. Never assume that a positive roadside test or blood result means you have no defence.
Do not risk your licence and liberty by facing this charge alone. Contact our expert motoring offence solicitors immediately for a confidential consultation and take the first critical step in building your strategic defence.