Sir David Alexander Warren, KCMG (born 11 August 1952) is a British diplomat, serving as HM Ambassador to Japan in the period 2008–2012.

[1] He retired from the Foreign and Commonwealth Office in January 2013, and served as chairman of The Japan Society in London from 2013 to 2019.

From 1987 to 1990, he served as Head of the Political Section in the British High Commission in Nairobi, Kenya.

He was seconded to the Cabinet Office (Office of Science and Technology) for two years from 1991, as the Head of the International Division, dealing among other issues with UK/Japan science and technology co-operation (the recycling of waste from nuclear reactors by British Nuclear Fuels being a key issue in this relationship).

[3] Following his second tour of duty in Tokyo, from 1998 to 2000 he was the Head of the FCO's Hong Kong Department.