Strict Liability (Criminal)

Most criminal offences require the prosecution to prove both a prohibited act (actus reus) and a blameworthy state of mind (mens rea). Strict liability offences depart from this by removing the need to prove fault for at least one element, usually to make regulatory or public-protection offences easier to enforce. A clear statutory example is drug-driving: the CPS's legal guidance on Road Traffic — Drink and Drug Driving explains that the offence at section 5A of the Road Traffic Act 1988 'is driving, attempting to drive or being in charge of a motor vehicle with a specified controlled drug in the blood or urine in excess of the specified limit for that drug', and that Parliament created it 'by introducing a strict liability offence to avoid the need to prove impairment.'

The guidance makes explicit why strict liability was chosen here: it 'brings enforcement of drug driving into line with that of drink driving' and is intended 'to enable more effective law enforcement to take place, with the aim of improving road safety by deterring potential drug drivers and bringing more drug drivers to justice.' The prosecution therefore only has to prove the defendant drove with the drug present above the specified limit — not that the defendant knew, or should have known, that their driving was actually impaired.