Gammon (Hong Kong) Ltd v Attorney-General of Hong Kong  AC 1
Strict Liability – Building Regulations – Public Safety
The contractor, project manager and site agent for building works in Hong Kong were charged with substantially deviating from approved plans which was likely to cause risk of injury to any person or damage to any property contrary sections 40(2A)(b) and 40(2B)(b) of the Hong Kong Buildings Ordinance (revised ed. 1981) (the Ordinance). The defendants were acquitted by the magistrate on the ground that it was necessary for the offence that there was knowledge that the deviation was material, which had not been proved. On Appeal, the Court of Appeal of Hong Kong held that mens rea was not required for the offences. The case was remitted to the magistrate.
The court looked to the case of Sweet v. Parsley  A.C. 132, which held that mens rea was an essential ingredient of every offence unless it is held not necessary for some established reason. The issue in question was when the presumption of mens rea could be displaced, and whether it was so displaced under the Ordinance, creating strict liability for the offences in question.
The presumption of law that mens rea is required for any criminal offence can only be displaced if (1) it is clear by the words of the statute creating the offence, or if the statute is concerned with an issue of social concern, such as public safety, and (2) the imposition of strict liability for the offence
“would be effective to promote the objects of the statute by encouraging greater vigilance to prevent the commission of the prohibited act.”
The effectiveness of the Ordinance in protecting public safety would be weakened if the mens rea of knowledge of the materiality of the deviations was required. The offences in question therefore created strict liability and the convictions were upheld.