Margaret Thatcher

Margaret Thatcher was a Prime Minister of Britain during the 1980s.

The Doctor, Roz Forrester and Chris Cwej lived for a short time in a housing estate during her time in power. (NA: Damaged Goods) The Doctor seemed to show some distaste towards her (DW: Father's Day)

Possibly non-canonical account
In one of several possible incarnations (his third, sixth or unknown other regeneration), the Doctor served as an advisor or consultant to her (SP: Doctor Who: The Ultimate Adventure)

Behind the Scenes

 * The character of Helen A from DW: The Happiness Patrol is believed to be based upon Margaret Thatcher.
 * The name of Rehctaht, the female villain of Turlough and the Earthlink Dilemma, comes from an anagram of Thatcher.
 * The reference to a female prime minister in Terror of the Zygons, several years before Thatcher's election, suggests that in the Doctor Who universe either Thatcher was elected PM earlier than in real life, or that another woman held the position before her.