A Member of Parliament (or MP) was an elected representative of the British public who voted in the Houses of Parliament. Each MP represented their own constituency. (TV: Aliens of London/World War Three)
In the early 20th century, James Skinsale served as the MP for Thurley. (TV: Horror of Fang Rock)
Carrying out a plan to stop the Starfire Project, nuclear weapons introduced to the UK in 1963, and assuming the name John Rutherford, after Ernest, the Seventh Doctor was elected as the MP for Lanarkshire, exploiting his constituents' distaste for the construction of American missile bases in the area. He enjoyed the experience, serving until the next year's election. (AUDIO: 1963: The Assassination Games)
In the 2000s, Harriet Jones served as MP for Flydale North, (TV: Aliens of London/World War Three) as did her counterpart in a parallel universe. (AUDIO: The Endless Night) She replaced the then-current Prime Minister, first in an acting capacity, (PROSE: Number Ten) then officially, (PROSE: Mars) following his murder by the Slitheen, relying on the fame she gained by surviving the devastating bombing of 10 Downing Street. (TV: Aliens of London/World War Three) In one timeline, she led the UK into a golden age over her three terms in office; (TV: World War Three) in another, she was compelled to step down early in her first term, after concerns about her health were seeded by Tenth Doctor, angered by her command to shoot down a Sycorax ship leaving Earth. (TV: The Christmas Invasion) When introducing herself, she flashed her ID card and stated her name and title, (TV: Aliens of London/World War Three, The Christmas Invasion, The Stolen Earth) to much annoyance, as she was already well-known. (TV: The Christmas Invasion, The Stolen Earth) Even after her resignation, she was "Harriet Jones, former Prime Minister". (TV: The Stolen Earth)
Joseph Green served as MP for Hartley Dale before he was murdered and replaced by Jocrassa Fel-Fotch Passameer-Day Slitheen, who assumed his identity before his death in March 2006. (TV: Aliens of London, World War Three, PROSE: Rose sighting confirmed)
During the ghost shifts of 2007, a ghost, actually a parallel Earth Cyberman in disguise, was elected MP for Leeds. (TV: Army of Ghosts)
Rex Matheson jokingly suggested that Gwen Cooper write to her MP to complain about her rendition. (TV: Rendition)