The Doctor's TARDIS (The Continuity Cap)

In an alternate reality, the Doctor's TARDIS was disguised as a red Telephone box instead of a blue Police box. The Doctor claimed it had been stuck that way for "several regenerations."

Due to the use of Continuity Cap, this TARDIS was swapped with the TARDIS of the prime Tenth Doctor. When the Doctor undid the effects of the Cap, the TARDIS was returned to its own universe. (COMIC: The Continuity Cap)