Part I recounts how writ of assistance search begin in customs enforcement and how, with the conciliar jurisdictions formerly sustaining them no longer available, customs powers to seek out smuggled goods ashore were established by statute in the Restoration period. Writ of assistance search arrived in 1662 with section 5(2) of the Act for Preventing Frauds and Regulating Abuses in His Majesty's Customs. Part II of the paper considers further legislative influences affecting British North America. Prominent among them was section 5(2)'s definition of what writ of assistance search was targeted upon: 'any Kind of Goods or Merchandize whatsoever, prohibited and uncustomed.' In the American colonies, a pronouncement from the English attorney general indicated that the writ of assistance was to be 'under the Seal of His Majesty's Court of Exchequer.' Since the process of the Court of Exchequer did not extend to the colonies, writ of assistance search could have no lawful place there. A convenient vehicle for remedying this was the extensive revamping of the colonial customs system in 1767. The onset of the new search provision, section 10 of the Revenue Act of 1767, is described in Part III of the paper. Part IV considers textual defectiveness in section 10 and its implications for later law in Canada. That the coherence of the original legislation has been diminished through historical evolution, leading to the existence of various anomalies in the present form of writ. The root of much of the error is concluded to be the legislation of 1767, whose wording produced much confusion about the nature of writs of assistance. The appendixes contain (1) the writ of assistance (English) of the mid-18th century, (2) a case for the opinion of Attorney General William De Grey touching the granting writs of assistance in America, 1768, and (3) the form of writ of assistance for British North America, 1768-69. Ninety-seven endnotes are provided.