Since the work of Beer, or at least since the studies of Andrews and Harper, no serious historian has failed to recognize that the British mercantile system did not bear too heavily upon the American colonies before 1763. In the first place, some regulations either directly and intentionally, or indirectly and unintentionally, fostered colonial development. In the second place, enforcement was often so lax and evasion so common that a number of regulations Lvere practically inoperative. Yet though the beneficent effects of ‘salutary neglect’ upon the American colonies have long been accepted, writers on Irish history have continued to assume that the mercantile system was applied to Ireland with devastating effectiveness. Was this indeed true? Or was British mercantilism in Ireland mitigated in the same ways as in the overseas colonies —by compensating advantages and by evasion? The present article concerns itself only with the latter point, the question of enforcement and evasion of British restrictions on Irish trade.