Shirley Williams

Shirley Williams was the Prime Minister of the United Kingdom.

During the Zygon gambit, the Prime Minister called Brigadier Lethbridge-Stewart and told him there was to be no public announcement and to take "discreet but resolute" action. (TV: Terror of the Zygons)

Mrs Williams appointed Robert Bertram as UNIT's new scientific advisor. He later convinced her that the Brigadier Lethbridge-Stewart and his men were plotting with aliens, and to let him use his pacification device during his concert. (PROSE: No Future)

According to the Eighth Doctor, Williams served between Thorpe and Thatcher. (PROSE: Interference - Book One)

Behind the scenes

 * In Terror of the Zygons, the female Prime Minister is not named, and in the novels her forename was not given, but the common-sense interpretation of the passage is that the author was referencing Shirley Williams.
 * In the real world, Williams never served as Prime Minister.