As far as his instructions went, his mission was successful, and, by a happy accident, he was able at Tunis and Tripoli to extort further from the rulers a promise that thereafter captives should be treated as in civilized countries; in other words, that they should no longer be reduced to slavery. Algiers refused this concession; and the admiral could not take steps to enforce it, because beyond his commission. The Dey, however, undertook to consult the Porte; and the fleet, with a few exceptions, returned to England, where it arrived towards the end of June.
Meanwhile British public feeling had become aroused; for men were saying that the outrages of the past had been rather welcome to the commercial selfishness of the country. The well-protected traders of Great Britain, shielded by her omnipotent navy, had profited by crimes which drove their weaker rivals from the sea. Just then news came that at the port of Bona, on the Algiers coast, where there was under the British flag an establishment for carrying on the coral fishery, a large number of the fishermen, mostly Italians, had been wantonly slaughtered by a band of Turkish troops. To insist, arms in hand, upon reparation for such an outrage, and upon guarantees for the future, would doubtless be condemned by some of our recent lights; but such was not then the temper of Great Britain. The government determined at once to send a fleet to the spot, and Lord Exmouth was chosen for the command, with such a force as he himself should designate. The gist of his instructions was to demand the release, without ransom, of all Christian slaves, and a solemn declaration from the Dey that, in future wars, prisoners should receive the usage accorded them by European states. Great Britain thus made herself, as befitted the obligation imposed by her supreme maritime power, the avenger of all those oppressed by these scourges of the sea. The times of the barbarians were fulfilled.