The aim of this policy is to strengthen the economic ties binding the countries of the British Empire together. Its supporters hold that the furtherance of Imperial Preference need not damage non-Empire trade; but it is difficult to imagine circumstances in which such injury would not arise. The idea of Imperial Preference is comparatively recent. Some writers refer to it as a kind of resurrection of older notions, and quote the Navigation laws which expired in the nineteenth century. The first practical step in the policy of tariff preference occurred in Canada in 1897 under the leadership of Sir Wilfrid Laurier. United Kingdom products were admitted at reduced rates. The introduction of Imperial Preference as a permanent feature of the tariff, with the openly avowed object of furthering Empire trade, occurred in 1919. The Government had an overwhelming majority in Parliament, and had been elected on a platform which included Imperial Preference as an essential feature.