Rose was a delegate to the London Conference of 1866. In 1869, Rose moved to England to practise law and acted as an unofficial representative of the Canadian government. His was one of the first missions of a partly diplomatic nature which Canada ever sent abroad. He was sent partly because his was perceived as being "gentlemanly" enough for the world of London politics. He worked for Canada's interests in trade and immigration, and lobbied for Canada's viewpoint on matter of Anglo-American relations. In this function, he answered directly to the Prime Minister, John A. Macdonald, since it was an informal position and was therefore not under the purview of the Governor General, meaning that communications could be kept secret from the Imperial Government. As well, Canada did not have a foreign affairs department at the time. This unusual situation did lead to a tradition of direct executive involvement in foreign affairs in Canada which still exists.