The Houses of Parliament were the collective term for the two bodies composing the legislature of the United Kingdom. They consisted of two houses convening in the Palace of Westminster: the Commons and the Lords. Parliament ratified laws and gave or withheld taxation desired by the British monarch.
The Palace of Westminster was the name given to successive structures on the same site in the city of Westminster, in central London, The 1840 palace included a massive clock tower on its north end, which held Big Ben.
In November 1605, Robert Catesby and Guy Fawkes plotted to blow up the Parliament as he opposed King James I's anti-Catholic regime. Lady Winters, a Rutan from the crashed ship, awoke from suspended animation and attempted to use the Gunpowder Plot to her advantage by propelling her ship with the explosion. The Eleventh Doctor safely placed the Palace of Westminster in Earth orbit, while he used a handful of gunpowder barrels belonging to the plotter Guy Fawkes to allow the ship still be launched. Having traced Winters' distress call, Sontarans and Rutans fought with one another inside Parliament while searching for these weapons, but were forced into ceasefire when the Doctor reprogrammed one of weapons to target the Rutans, risking one of the two species to kill their own kind. The Doctor returned the Palace to its rightful place and Fawkes was caught by the king's men before he could light the remaining 36 gunpowder barrels. (GAME: The Gunpowder Plot)
2-14 September 1752 were "lost" with the conversion from the Julian calendar to the Gregorian calendar. The London existence of that period was purchased from George II by Grandfather Paradox on behalf of Faction Paradox in the Gregorian Compact, and became their heartland known as the Eleven-Day Empire. The Empire was governed from the chamber of the House of Commons; the speaker's chair was empty, waiting for Grandfather Paradox's return. (PROSE: Interference)
In the early morning of 1 January 2005, the newly regenerated Eleventh Doctor, flew west over the Palace of Westminster, whilst clinging by his fingers from his TARDIS' doorway. He narrowly escaped ramming the clock tower, before climbing back aboard and being thrown nearly nine years back in time. (TV: The Eleventh Hour)
Later that year, after finding he had a listening device planted on him, the Eighth Doctor joked "if we're going to blow up Parliament, we'll need some first-rate gunpowder and some trustworthy Catholic horses." (COMIC: The Flood)
In 2009, in an alternate timeline created by Sarah Jane's actions in 1951 in which the world was destroyed, Luke, Sarah and the Trickster stood at the remains of the Palace of Westminster. (TV: The Temptation of Sarah Jane Smith)