This paper model is a TARDIS, designed by Dragnoz. The TARDIS (Time and Relative Dimension in Space) is a time machine and spacecraft in the British science fiction television program Doctor Who and its associated spin-offs.
A TARDIS is a product of the advanced technology of the Time Lords, an extraterrestrial civilization to which the program's central character, the Doctor, belongs. A properly maintained and piloted TARDIS can transport its occupants to any point in time and any place in the universe. The interior of a TARDIS is much larger than its exterior, which can blend in with its surroundings using the ship's "chameleon circuit".
In the series, the Doctor pilots an unreliable, obsolete TT Type 40, Mark 3TARDIS. Its chameleon circuit is faulty, leaving it stuck in the shape of a 1960s-style London police box after a visit to London in 1963. The Doctor's TARDIS was for most of the franchise's history said to have been stolen from the Time Lords' home planet, Gallifrey, where it was old, decommissioned and derelict. However, during the events of "The Doctor's Wife", the ship's consciousness briefly inhabits a human body, and she reveals that far from being stolen, she left of her own free will. During this episode, she flirtatiously implies that she "stole" the Doctor rather than the other way around, although she does also refer to him as her "thief" in the same episode.
The unpredictability of the TARDIS's short-range guidance has often been a plot point in the Doctor's travels. Also in "The Doctor's Wife", the TARDIS reveals that much of this "unpredictability" was actually intentional on her part in order to get the Doctor "where [he] needed to go" as opposed to where he "wanted to go".
Although "TARDIS" is a type of craft rather than a specific one, the Doctor's TARDIS is usually referred to as "the" TARDIS or, in some of the earlier serials, just as "the ship", "the blue box", "the capsule" or even "the police box".
Doctor Who has become so much a part of British popular culture that not only has the shape of the police box become more immediately associated with the TARDIS than with its real-world inspiration, the term "TARDIS-like" has been used to describe anything that seems to be bigger on the inside than on the outside. The name TARDIS is a registered trademark of the British Broadcasting Corporation.
In the program, the Doctor's TARDIS is an obsolete "Type 40 TT capsule" that he unofficially "borrowed" when he departed his home planet of Gallifrey. According to the Eighth Doctor Adventures novel The Gallifrey Chronicles by Lance Parkin, it previously belonged to a Time Lord named Marnal, who was, like the Doctor, something of a renegade. By the time of "The Pirate Planet," the Doctor had been travelling on board in time and space for 523 years and by the time of "The Doctor's Wife", he had been travelling in it for 700 years.
There were originally 305 registered Type 40s, but all the others had been decommissioned and replaced by new, improved models. However, the changing appearance of the primary console room over the years and the Second Doctor's statement in 1972's "The Three Doctors" - "Ah! I can see you've been doing the TARDIS up a bit. I don't like it." - suggests that the Doctor does upgrade the TARDIS's systems on occasion. The ship has also shown the ability to rebuild and reconfigure itself. In "The Eleventh Hour" the TARDIS completely changes after crashing, and the Doctor's comment "What have you got for me this time?" implies it is not the first time the TARDIS had undergone repairs of its own doing. In the 2007 Children in Need special "Time Crash" the Fifth Doctor complains to the Tenth Doctor that he had "changed the desktop theme!" In "The Doctor's Wife" the TARDIS says she has 30 desktops archived, although the Doctor has only changed it a dozen times "yet".
The TARDIS was already old when the Doctor first took it, but its actual age is not specified. The spin-off media have, on a number of occasions, had the TARDIS wait around for the Doctor for decades and even centuries in relative time. In "The Empty Child", the Ninth Doctor claimed that he has had "900 years of phone box travel", although "The Doctor's Wife" contradicts this by saying they've been travelling together for only 700 years. In the unfinished TV serial "Shada", fellow Time Lord Professor Chronotis said that the Type 40 models came out when he was a boy, which showed how old it was considering that he was on his final incarnation.
The 2011 episode "The Doctor's Wife" the "soul" of the ship is transferred into the body of a humanoid female called Idris, and enabling the Doctor to have a conversation with his craft. The TARDIS says that she deliberately allowed the Doctor to "steal" her, as she wanted to see the universe itself; in a reversal of the traditional view, the TARDIS claims to have stolen the Doctor. When he accuses the TARDIS of being unreliable, she defends herself by saying that she has always taken him where he needed to go, if not where he wanted. At the end of the episode, the TARDIS' soul is returned to the ship's systems.
In a later episode, "Let's Kill Hitler," the Doctor again speaks to the TARDIS by way of a voice/visual interface. In this instance, after providing options including an image of himself, as well as former companions Rose Tyler, Martha Jones and Donna Noble, the TARDIS manifests as an image of Amy Pond as a child. It is indicated, however, that the Doctor is only speaking to the "computer" controlling the TARDIS rather than the "soul" he interacted with earlier.