Before that the British heads of mission to the Holy See were styled Attaché resident at Rome and Envoy Extraordinary and Minister Plenipotentiary.

However, after the formation of the United Kingdom of Great Britain and Ireland an "unofficial official" was kept in Rome from the mid-nineteenth century, holding the title of representative to the Papal States.

[1] With the rise of Italian nationalism, the Papal States were conquered by the House of Savoy and a unified Kingdom of Italy was declared in 1861.

[1] This mission was maintained after the war for the perceived value of its prestige (a "quiet place for a not very distinguished diplomat") and the conflicts in Ireland, Malta, Quebec, and Australia, which had Roman Catholic dimensions.

[2] It has been claimed that the Minister was always a Protestant,[3] and that Francis Campbell, appointed ambassador in 2005, was "the first Catholic to hold the position of emissary of the Court of St James to the Holy See since the Reformation";[4] in fact, however, the first two 20th-century envoys, Sir Henry Howard and Count de Salis, were Catholics.