In 1831 and 1833 Great Britain entered into an arrangement with France for a mutual right of search within certain seas, to which most of the other powers acceded; and by the Ashburton treaty (1842) with the United States provision was made for the joint maintenance of squadrons on the west coast of Africa.
While his treaty with Lord Lyons in 1862 for the suppression of the slave trade conceded to England the right of search to a limited extent in African and Cuban waters, he secured a similar concession for American war vessels from the British government, and by his course in the Trent Affair he virtually committed Great Britain to the American attitude with regard to this right.
On the one hand the British claim did not, it is seen, go the length of the restriction Great Britain consented to place on her own right of search during the Boer War, seeming to apply only to the case of ships carrying conditional contraband.
Some difficulties which arose regarding the exercise by the British government of the right of search for contraband of war were also used to stimulate public feeling.
By the Milan Decree of the 17th of December 1807, he ordained that every ship which submitted to the right of search now claimed by Great Britain would be considered a lawful prize.