Ambassador Philip Kaiser served in every US Democratic Administration from President Truman to President Carter. A lifelong Anglophile, he was named US Minister to London by Secretary of State Dean Rusk because he knew more than half the Labour Government, including Harold Wilson, from his days as a Rhodes scholar at Oxford.

In his long service with the US Government he alternated as a senior Labour Department official, setting up postwar trade unions in Europe and Japan, and as the Ambassador to Austria, Hungary and Senegal.

President Carter named him as Ambassador to Hungary at the height of the Cold War in 1977, and Kaiser played a key role in persuading the US to return the Crown of St Stephen, a symbol of Hungarian nationhood, which had been in American custody to save it from falling into the hands of the Russians at the end of the war. Secretary of State Cyrus Vance was Kaiser’s key ally in arguing that returning the crown would encourage Hungary to turn to the West. Kaiser claimed later: “We returned the crown. We got a trade agreement. We opened up the country to the West and that relationship has continuously expanded.”

Kaiser managed another diplomatic coup as Ambassador to Senegal. At the height of the Cuban missile crisis he persuaded Senegal’s President, Leopold Senghor, to deny refuelling and landing rights to Soviet warplanes and access to the airport at Dakar. His warm relations with the Senegal leader paid off. Senghor told him he would let him have “anything President Kennedy wants”.

Kaiser’s long and close relationship with Britain began in 1933 when, as a student at the University of Wisconsin, he won a Rhodes scholarship to Balliol. Among his student friends at Oxford were Ted Heath, Denis Healey and Roy Jenkins. He was the first American to be elected president of the Junior Common Room – the social centre of the college. He was succeeded by Heath, Healey and Jenkins.

His tutor, who with Jenkins became a lifelong friend, was Sir Isaiah Berlin. He studied the British labour movement under the historian G. D. H. Cole but had some problems because Cole “didn’t like America or Americans”.

His contacts and friendships with British politicians of both parties proved invaluable years later when he was US Minister in London (1964-69) under Ambassador David Bruce. Lyndon Johnson was President and Harold Wilson Prime Minister at a time when the Vietnam war was a touchy issue between the two nations. From 1969 to 1977 he stayed on in Britain as a merchant banker and as chairman and managing director to the British branch of Encyclopaedia Britannica.

Philip Mayer Kaiser was born in Brooklyn in 1913, the ninth of ten children to Moishe Bear and Tema Kaiser. His parents were immigrants from Ukraine, and his mother never learnt English.

He attended New Utrecht High School and graduated from the University of Wisconsin in 1933. He returned to America from Oxford just before the war.

In 1949 he became assistant secretary of labour in the Administration of Harry Truman. In 1955 he became special assistant to Governor Averell Harriman. He was named Professor of International Labour Relations at American University, Washington, in 1959.

Throughout his career he was in and out of a succession of Democratic Administrations with a ringside seat of world affairs. Of the presidents he served, Truman was his favourite, because, Kaiser said, he was the closest to the people. In 1997 Kaiser published Journeying Far and Wide: A Political and Diplomatic Memoir.

Described as somewhat reserved and fastidious, he kept a good figure and into a late age was a fierce tennis player who believed in winning. He was also a great storyteller.

After his death his son, Charles, explained why all the Kaiser sons had become writers: “At the dinner table every night there was a competition to tell the best story. And if you didn’t tell the story as dramatically as possible, my father would lean forward and bellow, ‘Great Reporter! You buried the lead of the story’. After a while, you never buried the lead again.”

Kaiser is survived by his wife of 67 years, Hannah Greeley Kaiser, and his three sons, Robert, an associate editor of the Washington Post, David, a professor of history, and Charles an author and journalist.

Philip Kaiser, diplomat, was born on July 12, 1913. He died on May 24, 2007, aged 93