User:SOTO/Forum Archive/The Panopticon/@comment-1293767-20151029072618/@comment-27920493-20161214200349

The clear, indisputable and, most importantly, official multi-parters in the revived series are:

Series 1
Aliens of London / World War Three
The Empty Child / The Doctor Dances
Bad Wolf / The Parting of the Ways

Series 2
Rise of the Cybermen / The Age of Steel
The Impossible Planet / The Satan Pit
Army of Ghosts / Doomsday

Series 3
Daleks in Manhattan / Evolution of the Daleks
Human Nature / The Family of Blood
Utopia / The Sound of Drums / Last of the Time Lords

Series 4
The Sontaran Stratagem / The Poison Sky
Silence in the LIbrary / Forest of the Dead
The Stolen Earth / Journey's End

Series 5
The Time of Angels / Flesh in Stone
The Hungry Earth / Cold Blood
The Pandorica Opens / The Big Bang

Series 6
The Impossible Astronaut / Day of the Moon
The Rebel Flesh / The Almost People

Series 7
None (all episodes are officially standalones)

Series 8
Dark Water / Death in Heaven

Series 9
The Magician's Apprentice / The Witch's Familiar
Under the Lake / Before the Flood
The Zygon Invasion / The Zygon Inversion

Prior to Series 9, everything was clear cut. In Series 9, only TMA/TWF, UTL/BTF and TZI/TZI are clear two-parters, TGWD and TWWL are down to interpretation, and so are FTR, HS and HB. Some people consider TGWD and TWWL are two-parter, some people don't, some people consider FTR, HS and HB a three-parter, some people consider HS and HB a two-parter, and some consider them to be standalones. AGMGTW and LKH are official standalones, TGWD and TWWL aren't officially designated as a two-parter, and FTR, HS and HB aren't offically designated as a three-parter or a two-parter. Only the multi-parters listed above are officially designated, and therefore only they should be listed as such.