Type 12

Type 12 was a type of TARDIS used by Time Lords. The control systems of the Type 12 were hidden behind a wall panel.

It was a much older model than the Doctor's Type 40 TARDIS. Professor Chronotis owned a Type 12 Mark 1 TARDIS, which served as his rooms at St Cedd's College, Cambridge. This TARDIS model could hold another TARDIS within its force field and create a bridge between the two to walk through. Type 12 TARDISes were capable of interfering in an individual's time stream. It either did not have a chameleon circuit, or his didn't work. (PROSE: Shada)

Behind the scenes

 * The model of Professor Chronotis' TARDIS is not mentioned in the script book or finished TV: Shada, nor in the webcast or audio versions. In Gareth Roberts' 2012 novelisation, the Doctor identifies it as a "Type 12, Mark 1".