Prototype TARDIS

Prototype TARDISes, (AUDIO: Collision Course, PROSE: Cold Fusion) or Proto-TARDISes as Alice Obiefune called them, (COMIC: The Lost Dimension) were early TARDIS designs created under the rule of Rassilon in early Gallifreyan history. (PROSE: Heart of TARDIS, COMIC: The Lost Dimension) Some prototypes were retroactively numbered Type 1s. (PROSE: Heart of TARDIS) Several malfunctioning prototype TARDISes instigated Multi-Doctor Events when they threatened to destroy reality. (PROSE: Cold Fusion, Heart of TARDIS, COMIC: The Lost Dimension, AUDIO: Collision Course)

The first piloted TARDIS flight occurred on Henlen and involved a prototype TARDIS with six pilots including Tompino, Punshon, and Ankarrie. This flight was sabotaged by the Sirens of Time. (AUDIO: Collision Course)

The Fifth Doctor believed the Machine to be a prototype TARDIS. (PROSE: Cold Fusion)