Driving whilst unfit through drink and drugs

The offence of driving whilst unfit through drink or drugs is contained in section 4 Road Traffic Act 1998. This offence is used where the police suspect drug use or alcohol intoxication but have no samples to rely upon for a conviction. Evidence from a doctor who examines the suspect can be enough to convict and sometimes convictions are sought from the evidence of a police officer but as this evidence is only opinion it can be challenged.