What Is the Section 4 Offence?
Section 4 of the Road Traffic Act 1988 creates the offence of driving or being in charge of a mechanically propelled vehicle while unfit to drive through drink or drugs. Unlike the section 5 offence, it does not rely on exceeding a specific prescribed alcohol limit. Instead, the prosecution must prove that your ability to drive properly was impaired by alcohol.
This offence is typically charged when a breath, blood or urine specimen was not obtained, or when the reading is below the legal limit but the driver was visibly impaired. It can also be charged alongside the standard drink driving offence. The section 4 offence covers both driving and being in charge of a vehicle.
The offence applies to any mechanically propelled vehicle, not just motor vehicles. This means it can extend to vehicles such as electric scooters and ride-on lawnmowers. The vehicle must be on a road or other public place at the relevant time.
How Does Unfit to Drive Differ from Standard Drink Driving?
The standard drink driving offence under section 5 is based on a specific alcohol reading exceeding the prescribed limit. It is an objective test: either you are over the limit or you are not. The section 4 offence is fundamentally different because it requires evidence that your driving ability was actually impaired, regardless of the exact level of alcohol in your system.
This distinction has important practical consequences. Under section 4, you can be convicted even if your alcohol level is below the legal limit, provided the prosecution can show impairment. Equally, a person over the legal limit could potentially argue under section 4 that they were not impaired, though this would be unusual.
The evidential requirements differ significantly. Section 5 cases rely primarily on the result of a breath, blood or urine test. Section 4 cases depend on observations of impairment, field tests, medical examinations and witness testimony. This often makes section 4 cases more open to challenge.
Evidence of Impairment
Field Impairment Test
The field impairment test is a series of physical and cognitive tasks administered by a trained police officer, usually at the roadside or at the police station. It typically includes the walk and turn test, the one-leg stand, the finger-to-nose test and the Romberg test, which assesses balance and time estimation.
Officers are trained to observe specific indicators of impairment during each test. These include swaying, using arms for balance, stepping off the line, inability to follow instructions and poor coordination. The results are recorded on a standard form and can be used as prosecution evidence in court.
Medical Examination
A forensic medical examiner or registered healthcare professional may conduct a clinical examination at the police station. This examination assesses coordination, pupil reaction, speech patterns, demeanour and overall physical condition. The doctor records their findings and provides an opinion on whether the subject is fit to drive.
The medical examination report carries significant weight in section 4 cases. However, it is an opinion based on clinical observations and can be challenged. A defence solicitor can question the methodology, qualifications of the examiner, and whether the observations are consistent with impairment or could have an alternative explanation.
Witness Evidence
Witness testimony from police officers and members of the public can support a charge of being unfit to drive. Officers may describe the manner of driving, the defendant's appearance, their behaviour during the stop and any signs of intoxication such as slurred speech, unsteadiness, bloodshot eyes or the smell of alcohol.
Civilian witnesses who observed the driving or the defendant before or after the incident can also give evidence. Dashcam and CCTV footage increasingly plays a role in these cases. Defence solicitors can cross-examine witnesses to challenge the accuracy and reliability of their observations.
Penalties for Being Unfit to Drive Through Drink
The penalties for the section 4 driving offence mirror those for standard drink driving under section 5. The maximum sentence is 6 months imprisonment, an unlimited fine and a mandatory driving disqualification of at least 12 months. The minimum ban increases to 36 months for a second offence within 10 years.
For the section 4 in charge offence, the maximum penalties are 3 months imprisonment, an unlimited fine and 10 penalty points. A discretionary driving ban may be imposed. The no likelihood of driving defence under section 4(3) is also available for the in charge variant of this offence.
Sentencing follows the same guidelines as section 5 cases, with the court assessing the level of impairment and any aggravating or mitigating factors. A conviction results in a criminal record and the relevant DR endorsement code on your licence for 11 years.
Defences to a Section 4 Charge
The subjective nature of the section 4 offence creates more scope for defence than a straightforward reading-based charge. A solicitor can challenge the evidence of impairment by questioning the reliability of the field impairment test, the qualifications and methodology of the medical examiner, and the accuracy of witness observations. If the prosecution cannot prove impairment beyond reasonable doubt, the case must be dismissed.
Other defences include arguing that the impairment was caused by a medical condition rather than alcohol, that you were not driving or in charge of the vehicle, or that the vehicle was not on a road or public place. For the in charge variant, the statutory defence of no likelihood of driving is available. Each case turns on its own facts, and early legal advice is essential to identify and develop the strongest defence.