Proprietary Articles Trade Association v. Attorney General of Canada
Proprietary Articles Trade Association v. Attorney General of Canada, A.C. 310 is a famous Canadian constitutional decision of the Judicial Committee of the Privy Council on the Constitution's criminal law power under section 91(27).
Lord Atkin, writing for the Council, rejected the previous interpretation of criminal law in Canada by Lord Haldane in the Board of Commerce case as it froze the scope of criminal law to what was considered criminal at the time of confederation in 1867. Instead, Atkin offered a new definition:
The criminal quality of an act cannot be discerned by intuition; nor can it be discovered by reference to any standard but one: Is the act prohibited with penal consequences?
This statement suggested two requirements for criminal law. It must consist of a prohibition and must impose a prison sentence.
Atkin's definition only lasted until 1949 when it was once again redefined much more narrowly in the Margarine Reference case.