The Interzone was a transitional space between zones on the planet Bortresoye, in the Divergent Universe. The environment appeared to be a hazy white space with a very short sight distance, and a humming/buzzing background. Access to and from this space was through various Interzone portals, controlled by the Kro'Ka.
The Eighth Doctor, Charley Pollard and C'rizz used the Interzone to visit various zones on Bortresoye whilst the TARDIS was temporarily lost to them. (AUDIO: The Creed of the Kromon, The Last, Caerdroia and others)