Episode 31 - The Constant Companion

In Focus: TARDIS

The most reconigizable part of "Doctor Who" is that time traveling, blue police box, the TARDIS. She's been a constant presence, but how much do we know about this Time Lord ship? Jessica and Phillip examine the TARDIS as an active character in the show, from how she reacts to companions to how she communicates with the Doctor. 

In their look into the TARDIS library, the couple co-hosts examine "Attack of the Cybermen," when the Sixth Doctor actually (kinda) fixes the TARDIS' chamelon circuit, and we see it appear as non-police box objects.
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What would be the best substitute for the police box as a new TARDIS appearance? What would be the worst?