… is from page 277 of the 1993 2nd edition of Rondo Cameron’s A Concise Economic History of the World:
Also in the aftermath [of the 1846 repeal of the British Corn Laws], Parliament cleared the books of much of the old “mercantilist” legislation, such as the Navigation Acts, which were repealed in 1849. As the new party alignments settled down in the 1850s and the 1860s, with Gladstone as chancellor of the exchequer for much of the time, an uncompromising policy of free trade emerged. After 1860 only a few import duties remained, and those were exclusively for revenue on such non-British commodities as brandy, wine, tobacco, coffee, tea, and pepper. In fact, although most tariffs were eliminated altogether and the rates of duty on all others were reduced, the increase in total trade was such that customs revenue in 1860 was actually greater than that of 1842.
Note two facts. First, near-universal and unilateral free trade was indeed the policy of Great Britain in the decades following the repeal of the Corn Laws. Second, the Laffer curve describes an important truth.