TARDIS' interior was initially filled with electronics and masses of wiring. (NOTDWU: Dr. Who and the Daleks) This was later changed to a neater arrangement with control consoles in silver casings. (NOTDWU: Daleks' Invasion Earth 2150 A.D.)
TARDIS was described by Dr. Who as a matter transmitter, breaking itself and everything inside it into constituent electrical charges, which were sent to the destination. (NOTDWU: Dr. Who and the Daleks)
Dr. Who told Tom Campbell that TARDIS could travel to any age, any planet and any universe, implying the machine could travel to alternate universes safely and easily, and could return to its original universe with little to no trouble. (NOTDWU: Daleks' Invasion Earth 2150 A.D.)
Behind the scenes
- The interior of TARDIS (not called "the TARDIS" in the films) did not use the familiar television set-up of a central console with walls on each side, but a more random assortment of technological apparatus.
- TARDIS seemed to lack a lock and key mechanism, unlike the television TARDIS. Several people entered the machine — Ian Chesterton, Alydon and Tom Campbell to name a few.