what defence mechanism was it built with?
A force field, a tribophysical waveform macro kinetic extrapolator, and the Hostile Action "Dispersal" System.
TARDIS
One of the main TARDIS defenses is a force field. The field is seen in use in "The Runaway Bride" (2006), when the Tenth Doctor and the Bride, Donna Noble, are trying to escape the Empress of the Racnoss and in "The Beast Below" (2010), when the Doctor is showing Amy Pond the wonders of the universe. In "Journey to the Centre of the TARDIS" (2013), the Eleventh Doctor turns off the shields by putting the TARDIS on "basic mode" for his companion, Clara, to operate. Another device, a tribophysical waveform macro kinetic extrapolator, is installed to generate a force field in the episode "Boom Town" (2005) and is later used to protect the ship from Dalek missiles in "The Parting of the Ways".

Another defensive feature is the Hostile Action Displacement System (HADS), which can (if switched "on" by the ship's operator) teleport the ship away if it is attacked ("The Krotons", 1968) or in great danger ("Cold War", 2013). The Hostile Action "Dispersal" System can, if the TARDIS is threatened
when is the new season of doctor who starting UNANSWERABLE what is this series? It is a British science fiction television programme. what does it deal with? It depicts the adventures of a Time Lord called "the Doctor", an extraterrestrial being, to all appearances human - he explores the universe in a time-travelling space ship called the TARDIS - the exterior appears as a blue British police box. what are the features of the space ship mentioned above? TARDISes are built with a chameleon cirtcuit, a piece of technology that allows them to change the exterior form of the ship to blend into the environment of whatever time or place it lands; is famously "bigger on the inside", with the interior being a whole separate dimension containing an infinite number of rooms, corridors and storage spaces. what relation does consciousness has with it? The "soul" of the ship is transferred into the body of a humanoid female called Idris, enabling the Doctor to have a conversation with his craft.
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TARDIS [SEP] Defences
When fully active, the TARDIS's outer defences are (nearly) impenetrable. In the last episode of "The Armageddon Factor" (1979), the Black Guardian is unable to enter the TARDIS after the Doctor activates "...all of the TARDIS's defences..." Similarly, when being chased by an Auton in "Rose" (2005), the Doctor reassures future companion Rose Tyler that "the assembled hordes of Genghis Khan couldn't break through those doors, and believe me, they've tried." However, in "Journey's End" (2008) the Tenth Doctor states that the Daleks, created and led by Davros, would have no problem breaching the TARDIS defences. "They're experts at fighting TARDISes, they can do anything.