Portaloo

STARDIS had a form of a portaloo and emitted the sound of toilet flushing during materialisation and dematerialisation. (AUDIO: The One Doctor)

The Monk's TARDIS once took the shape of a portaloo. (COMIC: Follow That TARDIS!)

Once aboard Nerva Beacon, one crewmate told the Fourth Doctor that he thought the TARDIS was "a convenience". Whilst the Doctor disagreed completely, Sarah Jane Smith and Harry Sullivan not only agreed but also found it a rather amusing comparison. (AUDIO: Return of the Cybermen)

The Seventh Doctor's companion Hex once compared the Doctor's TARDIS to a portaloo, (PROSE: Six Impossible Things Before Breakfast) as did a Dollar Intergalactic employee. (COMIC: Terrorformer) Even Ace, while talking to Hex, referred to the TARDIS as "the portaloo". (PROSE: Six Impossible Things Before Breakfast)