Westendorp v R, [1983] 1 S.C.R. 43 was a decision of the Supreme Court of Canada on the scope of the federal Parliament's criminal law power under section 91(27) of the Constitution Act, 1867. A unanimous Court found that a municipal by-law that prohibited standing in the street for the purpose of prostitution was in the nature of a criminal law prohibition and therefore ultra vires of the provincial constitutional authority. The decision surprised many legal scholars who considered it to be inconsistent with previous Supreme Court cases where provincial laws of a moral nature were upheld under the provincial power (see Canada (AG) v Montreal (City of), [1978] and Nova Scotia (Board of Censors) v McNeil [1978]). This was also the first case where the Canadian Charter of Rights and Freedoms