William Alistair Harrison CMG CVO (born 14 November 1954[1]) is His Majesty's Marshal of the Diplomatic Corps.

[3] From 1987 till 1992, he was based in New York City as part of the UK Mission to the United Nations.

He returned to London and became Deputy Head of the Middle East Department at the Foreign and Commonwealth Office, a position that he held until 1995 when he was once more posted to Warsaw, Poland.

With this experience, he returned to the Foreign Office in London to head the United Nations Department between 2003 and 2005.

[6] In 2020, he received Bene Merito honorary badge of the Minister of Foreign Affairs of Poland.