Faced with the ending of British imperial preference when the British Corn Laws, tariffs on food imported to Britain, were repealed in 1846, the Canadian business community based in Montreal looked south. Merchants threatened to push for annexation to the United States unless London negotiated a free trade deal. In 1854, they achieved what they wanted by the Elgin–Marcy Treaty, which listed most Canadian raw materials and agricultural produce, especially timber and wheat, as goods to be admitted duty-free to the US market. The treaty ended the US 21% tariff on natural resource imports.