Prime Minister of the United Kingdom

The Prime Minister was the political head of the United Kingdom. (Several other nations had the same office title.)

History

 * For ease of identification, the summary below bolds the lists of known Prime Ministers.

Early 20th century
The Doctor mentioned meeting and drinking with David Lloyd George (DW: Aliens of London)

The Doctor spoke of having met and known then-Prime Minister Winston Churchill during World War II. In his sixth incarnation, he encountered Churchill twice before he became Prime Minister and prevented the Players from altering the man's timeline. (PDA: Players) Churchill would serve as Prime Minister again in the 1950s. (DW: The Idiot's Lantern)

1960s through 1980s
Harold Wilson was Prime Minister in the late 1960s; his support in the 1970 general election was eroded by a series of disasters at scientific research facilities in 1969-70, such as Wenley Moor. (MA: Who Killed Kennedy referencing DW: Doctor Who and the Silurians). Edward Heath suceeded him Prime Minister, but his government quickly came under fire due to the chaos at a Britain-hosted peace conference. (MA: Who Killed Kennedy, referencing DW: The Mind of Evil)

At some point, "Jeremy" came to power, and Brigadier Lethbridge-Stewart consulted with him. (DW: The Green Death) A few years later, the Brigadier conferred with an unnamed female Prime Minister (DW: Terror of the Zygons), though not unnamed if perhaps he spoke with Margaret Thatcher. During the late 1980s, the Doctor would also act as a consultant to Thatcher. (SP: Doctor Who: The Ultimate Adventure) Despite this, he would later show distaste towards her. (DW: Father's Day, Tooth and Claw)

1990s
On 6 May 1997, an unnamed male Prime Minister, a man, was assassinated by his own bodyguard while in Washington during the Lord Xznaal crisis. (NA: The Dying Days) At some point following this, Tony Blair became Prime Minister. (DW: Rise of the Cybermen)

2000s
In the early 21st Century, Sherilyn Harper of the far-right New Britannia party came extremely close to being voted in as Prime Minister. (BFA: The Fearmonger)

An unnamed male Prime Minister incurred the wrath of ICIS and related interests in the government due to increased links with the European Union. After he signed the Euro-Combine Treaty, this conspiracy started a wave of terrorism in the hopes of getting him to declare martial law and give ICIS the power to take charge. He later declared he would shut down ICIS over this (BFA: The Longest Night), but they briefly remained in existence for a while longer. (BFA: The Wasting)

In early 2006, following the 2005 general election, the United Kingdom had a male Prime Minister (possibly the same one and possibly Tony Blair). He was killed by the Slitheen, and the position of Acting Prime Minister was then assumed by Joseph Green, actually Jocrassa Fel-Fotch Passameer-Day Slitheen wearing the slain Green's skin. Jocrassa and his brothers were later killed by a missile strike on 10 Downing Street. (DW: Aliens of London / World War Three) Following the Slitheen crisis, the real Prime Minister's death was officially deemed an accident. (WEB: whoisdoctorwho.co.uk)''

By Christmas, Harriet Jones had taken over from him, though she earned the disfavour of the Doctor, who ensured her political downfall. (DW: The Christmas Invasion)

Jones lost power in early 2007, after the events of The Christmas Invasion, and a new Prime Minister was appointed. This Prime Minister was accused by Jack Harkness of leaking documents about Torchwood operations to the Opposition (TW: Greeks Bearing Gifts).

A male Prime Minister replaced him. Jack Harkness accused this PM of leaking documents about Torchwood operations to "the opposition" (presumably UNIT) (TW: Greeks Bearing Gifts).''

In May 2008 "Harold Saxon", i.e. the Master, was elected. Shortly after his election, he gassed his entire cabinet and introduced the Toclafane to the human race. (DW: The Sound of Drums)

Following on from "Saxon", Aubrey Fairchild became Prime Minister (NSA: Beautiful Chaos). During the 2009 Dalek invasion, Gwen yelled to Jack that they have lost contact with the Prime Minister's plane and he is implied to have died.(DW: The Stolen Earth)

2010s
Brian Green would succeed Fairchild circa 2010. (TW: Children of Earth:?)

Alternate timelines
In the Earth of Cybus Industries, Great Britain had the office of President rather than Prime Minister. (DW: Rise of the Cybermen / The Age of Steel)

Behind the Scenes
The "Jeremy" reference in The Green Death had been a cheeky implication by the production team meant to imply that Liberal Party candidate Jeremy Thorpe would win the contemporary general election. (The production team assumed at the time that the UNIT stories actually took place in the near future.) In real life, he did not manage to get elected.

The Terror of the Zygons reference to an unnamed female Prime Minister is assumed to be a reference to cabinet minister Shirley Williams, though she was never a Labour Party leader in real life.

According to Doctor Who: The Writer's Tale, originally in The Stolen Earth or Journey's End, PM Fairchild Originally, PM Fairchild was going to be exterminated by the Daleks at Westminster.