In 1876, Pauncefote returned to London as Assistant
Permanent Under-Secretary of State for the Colonies. He soon transferred to the Foreign Office where he took over the
same post at the
Foreign Office in 1876. Pauncefote was promoted
Permanent Under-Secretary of State for Foreign Affairs in 1882. He was appointed first British delegate to the Suez Canal Conference in Paris in 1885, and was rewarded for his services in this respect with appointment as a Knight Grand Cross of the
Order of St Michael and St George (GCMG). In 1888, he became a Knight Commander of the
Order of the Bath (KCB), and the following year was sent to the United States as Envoy Extraordinary and
Minister Plenipotentiary. His position was elevated in 1893 to
Ambassador, and it made him the Dean of the Diplomatic Corps because Ambassador is superior to all other
Envoys dispatched by other countries. He and American secretary of state
Richard Olney in January 1897 negotiated an arbitration treaty, but the U.S. Senate, jealous of its prerogatives, refused to ratify it. He was Britain's representative at negotiations and signatory of the
Tripartite Convention in 1899 that partitioned the Samoan islands. In 1901 he negotiated the
Hay–Pauncefote Treaty (with American Secretary of State
John Hay), nullifying the
Clayton–Bulwer Treaty of 1850, and giving the United States the right to create and control a canal across Central America. Having finally become a Knight Grand Cross of the
Order of the Bath (GCB) in 1892, Pauncefote the following year became the first
British Ambassador to the United States. He was sworn of the
Privy Council in 1894 and raised to the peerage as
Baron Pauncefote, "of
Preston, Dymock in the County of
Gloucester", in 1899.
Preston Hall, near
Dymock, in Gloucestershire, was a former seat of the Pauncefote family. ==Marriage and issue==