TARDIS key A TARDIS key was the key to the exterior door of a TARDIS . They could be found in a variety of shapes and designs . Whatever the key ' s shape and size , and whatever form the TARDIS ' outer plasmic shell , the key would fit a lock somewhere in the structure . Function . Use of a TARDIS key enabled entry to a locked TARDIS in the manner of other types of keys , and was not limited by the reconfigurable shape of either the key itself or the outer plasmic shell of the TARDIS . Different TARDIS shells had different locks , whether obvious or hidden , and a TARDIS lock would accept its key even if it was physically larger than the lock . ( PROSE : " Interference - Book Two " ) The Doctor ' s TARDIS key . Function . The barrier on the Doctor ' s TARDIS , a type 40 , was a double curtain trimonic . As such , the Chancellery Guard needed the model ' s cypher indent key to gain entry without the actual key , as opposed to other methods of forced entry . ( TV : " The Deadly Assassin " ) . In its police box disguise , entry was allowed by inserting a key into the lock , just like a real police box . ( TV : " Doctor Who " , " Rose " and others ) However , the locking mechanism did not respond to police - issued keys . ( TV : " Blink " ) According to Susan Foreman , the lock had a defence mechanism in which there were twenty one different holes inside the lock , one being the right place and other twenty being wrong . If a mistake was made , the whole inside of the lock would melt . ( TV : " The Survivors " ) The Brigadier was prevented from opening the TARDIS in the Third Doctor ' s absence , because of the metabolism detector on the lock . ( TV : " Spearhead from Space " ) Nevertheless , there were occasions on which strangers were able to successfully use the Doctor ' s key , suggesting either a flaw in the metabolism detector or a choice on the part of the TARDIS . ( TV : " The War Machines " , " Doctor Who " , " Blink " ) The lock could be manually secured from inside the TARDIS , preventing even authorised individuals from using the key to unlock the doors from the exterior . ( TV : " The Dalek Invasion of Earth " , " Utopia " ) At some point shortly before the Tenth Doctor ' s regeneration , the TARDIS had a system that allowed him to lock the TARDIS remotely using a fob ( as a joke , the TARDIS roof light flashed and a alarm chirp sound was heard , similar to that used on vehicles on Earth ) . He was also able to open the door remotely . ( TV : " The End of Time " ) There were occasions on which the Doctor or his companions needed to use the key to " lock " the doors , ( TV : " Strangers in Space " ) while on others ( TV : " Spearhead from Space " , " The Christmas Invasion " ) the act of merely closing the doors locked the TARDIS . It was evident that the TARDIS ' lock could be set to secure either automatically or manually . However , a key was not always needed to open a TARDIS . During the Doctor ' s first encounter with River Song ( from his point of view ) , she remarked that she had witnessed his future self open the doors of the TARDIS by snapping his fingers . The Tenth Doctor reacted with disbelief , but later successfully opened the doors in this fashion . ( TV : " Forest of the Dead " ) After regenerating into his eleventh self , the Doctor again opened the TARDIS by snapping his fingers , demonstrating that this method had become a reliable way for him to do so . ( TV : " The Eleventh Hour " ) The Doctor did , however , continue to make regular use of his key to unlock the TARDIS . ( TV : " The Time of Angels " , " Flesh and Stone " , et . al . ) Design . The key to the Doctor ' s TARDIS took several forms , as the key was able to change shape with the chameleon circuit . ( AUDIO : " The Alchemists " ) The First and Second Doctor s used a key which resembled a plain Earth lock , such as might be used with a genuine police box . The Third Doctor started out with the same key . ( TV : " Spearhead from Space " ) At some point in his third life , the Doctor began experimenting with new designs for his key , coming up with several alternative designs before settling on a spade - shaped silver key . After his regeneration , the Fourth Doctor experimented with even more radical designs , which included a double - helix apparently made of plastic , before eventually going back to the spade and Yale styles . ( PROSE : " Interference - Book Two " ) The Yale key was also used by the Fifth ( TV : " Four to Doomsday " ) and Sixth Doctor s . The Seventh Doctor used yet another design , incorporating the Seal of Rassilon with a fan - shaped motif . ( TV : " Ghost Light " ) The Seventh Doctor eventually went back to the spade key , which the Eighth Doctor initially continued to use . ( TV : " Doctor Who " ) At some point , the Eighth Doctor returned to using the Yale key . ( PROSE : " The Crooked World " , " History 101 " ) The Ninth , ( TV : " Aliens of London " , " Father ' s Day " ) Tenth , ( TV : " 42 " ) and Eleventh Doctor s ( TV : " The Eleventh Hour " ) used Yale - type keys in a gold / brass colour as opposed to earlier Doctors ' silver - coloured Yale keys . Abilities . Beyond simply unlocking the TARDIS doors , the Doctor ' s TARDIS key has often displayed other uses and characteristics . The Doctor ' s TARDIS key could be used to open TARDISes other than his own . ( TV : " The Mark of the Rani " ) The TARDIS key glowed and grew warm when the TARDIS was about to materialise nearby ( TV : " Aliens of London " ) or when an incapacitated TARDIS had finished rebuilding itself . ( TV : " The Eleventh Hour " ) This feature was also exhibited when Susan Foreman ' s key , long disused , began to glow when the Eighth Doctor came back to Earth during the Dalek s ' second attempt to move the planet in the 22nd century . ( AUDIO : " Lucie Miller " ) When the TARDIS fell through a wound in time , the key was hot and glowed , indicating that it was still connected to the TARDIS , leading the Ninth Doctor to use the key in order to call the TARDIS . The Doctor warned that if the key was touched by anything , it would cause the now - re - materialising TARDIS to disappear . After Rose Tyler came into contact with her younger self , it caused a Reaper to emerge which consumed the Doctor . As it tried to fly away , the Reaper touched the key which destroyed it and caused the TARDIS to disappear . ( TV : " Father ' s Day " ) As a part of the TARDIS , keys had low - level perception filter properties . The Tenth Doctor was able to tune the keys into the psychic network created by the Master to extend these properties to an individual wearing a key . ( TV : " The Sound of Drums " ) The key could remotely lock the TARDIS from a distance , similar to some car keys . ( TV : " The End of Time " ) The key could be used to place the TARDIS one second out of sync with the rest of the universe , preventing it from being seen . ( TV : " The End of Time " ) The key could be modified to track and locate the TARDIS , allowing the Doctor to find the TARDIS if it was within a hundred years of his position . ( COMIC : " The Forgotten " ) When Sarah Jane Smith left the key in the lock without opening the door , it cancelled the pause control . The TARDIS travelled to its set coordinates on Earth , instead of remaining in the copy of Devesham created by the Kraal . ( TV : " The Android Invasion " ) The Eleventh ( TV : " The Time of the Doctor " ) and Twelfth Doctor ( TV : " Death in Heaven " ) were able to summon the TARDIS to him using the key . The keys were very resilient and could only be destroyed by being dropped into lava . ( TV : " Dark Water " ) Known copies . The Doctor usually had his TARDIS key on his person at any given time . There were numerous other known copies of his key . A spare key was made by the First Doctor to replace one Marco Polo had taken away . Marco took away the spare as well and later returned both . ( TV : " Marco Polo " ) Susan ' s first key was destroyed by the Doctor whilst shorting out static electricity production in the Dalek City . Just before he destroyed it , he promised to make her a new one . ( TV : " The Ordeal " ) Susan ' s second key was seen when Susan locked the TARDIS aboard a human spaceship in proximity of the Sense Sphere . ( TV : " Strangers in Space " ) Later , knowing she would likely never see the TARDIS again , she intentionally abandoned this key in the dirt on the bank of the River Thames , after her grandfather helped her decide to start a new life in the 2160s by locking her out of the TARDIS . ( TV : " The Dalek Invasion of Earth " ) Susan later recovered her key . ( AUDIO : " Lucie Miller " ) A key that fell from the Doctor ' s cloak was picked up by Ben Jackson . ( TV : " The War Machines " ) During their travels with the Fifth Doctor , both Tegan Jovanka and Nyssa were given their own keys to the TARDIS ( AUDIO : " Hexagora " ) as was Peri Brown . ( PROSE : " Fascination " ) Peri still had her key when travelling with the Sixth Doctor . ( PROSE : " House " ) A spare copy of the spade - type key kept by the Seventh and Eighth Doctors was stored in a secret compartment in the TARDIS ' outer shell . It was used by the Eighth Doctor when Chang Lee had stolen the original from his possessions . ( TV : " Doctor Who " ) The Eighth Doctor intended to give Lucie Miller a TARDIS key with a Christmas - themed musical ringtone as a Christmas present . ( AUDIO : " Relative Dimensions " ) Sarah Jane Smith took a double - helix shaped key , apparently made of plastic , with her when she left the TARDIS . ( PROSE : " Interference - Book Two " ) Anji Kapoor had a Yale design key , ( PROSE : " The Crooked World " ) as did Rose Tyler , ( TV : " Aliens of London " ) Jack Harkness , ( TV : " The Parting of the Ways " ) Martha Jones ( TV : " 42 " ) and Donna Noble . ( TV : " The Sontaran Stratagem " ) Martha and Jack ' s keys were modified into perception filter s . ( TV : " The Sound of Drums " ) The Ninth Doctor kept at least one copy of his key , the one he gave to Rose Tyler , on a long metal chain with a D - shackle at the end . Adam Mitchell was briefly in possession of Rose ' s copy of the key , which was nearly stolen by the Editor . This further proved to the Doctor that Adam was unfit for companion life . ( TV : " Aliens of London " , " The Long Game " ) Tenth Doctor opted to keep one on a cord of twine that the Weeping Angel s stole off him while transporting him to 1969 . ( TV : " Blink " ) The Eleventh Doctor , by the end of his life , wore a copy on a cord around his neck , which he gave up to Tasha Lem . When he and Clara needed to escape the Weeping Angels on Trenzalore , he produced another key that he kept underneath his wig to summon the TARDIS around the two - " the old ' key in the quiff ' routine . " ( TV : " The Time of the Doctor " ) A spade key was worn on a choker by Romana II . ( WC : " Shada " ) The Claw Shansheeth attempted to conjure a copy of the Doctor ' s TARDIS key through use of a memory weave on Sarah Jane and Jo Jones ' minds . Sarah Jane and Jo overloaded the device and the partially created key disappeared . ( TV : " Death of the Doctor " ) Clara Oswin Oswald received a copy of the key , although she lost it when the ice sculpture governess pulled her out of the TARDIS . However , the Doctor returned it to her while she was dying . ( TV : " The Snowmen " ) At some point farther into their adventures than with other companions , the Doctor gave the original Clara Oswald a key to the TARDIS . ( TV : " The Time of the Doctor " ) To Clara ' s knowledge the Twelfth Doctor had seven keys in his possession , hidden in different places inside his TARDIS . Clara attempted to steal them and blackmail the Doctor into saving Danny Pink , but the Doctor outwitted her and helped her regardless . ( TV : " Dark Water " ) At this point in time she did not appear to have her own key , as none was produced by her during her blackmail attempt ; she subsequently reacquired a key ( TV : " Sleep No More " ) which she still possessed after her extraction from the trap street as she was later able to enter the Doctor ' s TARDIS before returning it to him . ( TV : " Hell Bent " ) Other TARDIS keys . The Chancellery Guard on Gallifrey had cypher indent keys , which were TARDIS master keys of varying shapes under the control of the Castellan ' s office . Some of these worked by being inserted into the keyhole , some worked by simply being held near the lock . Cypher indent keys were specific for each model of TARDIS . ( TV : " The Deadly Assassin , The Invasion of Time " )