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                       K9  
                         (1977 – 1981, 1983, 2006 & 2008) | 
                      
                     
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                       John
                         Leeson 
                         (voice only)  | 
                      
                     
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                           |  John
                             Leeson was born in 1943 and after spending time
                             working in a bookshop and then as a porter at Leicester
                             Royal Infirmary he joined RADA. Work in repertory
                             theatre, pantomimes and television soon followed.
                             His appearances on television included Dads Army and
                             the children's show Rainbow where he played
                             the original "Bungle the Bear" in 1972. He was also
                             involved in the setting of the questions in Mastermind.
                             However, it was his involvement in voice-overs which
                             brought him eventually to Doctor Who. He
                             was cast as the Nucleus and as well as K9 in "The
                               Invisible Enemy" and he was also seen onscreen in "The
                                 Power of Kroll". He played K9's voice between 1977
                             and 1981 (except for Season
                               17 when he took a break
                             from the part). He even agreed to return in the
                             1981 spin-off programme K9 and Company: A Girls
                               Best Friend along with Elisabeth
                                 Sladen and again in the 20th anniversary special "The
                                   Five Doctors" in 1983. Since leaving Doctor Who John
                             Leeson has continued to provide voice-overs for
                             the BBC. He also appeared in the 1988 Reeltime Pictures
                             video production Wartime along with John
                               Levene. | 
                          
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                       David
                         Brierley 
                         (voice only)  | 
                      
                     
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                           |  Born
                             in Yorkshire in 1935 David Brierley has worked in
                             numerous television programmes including Blind
                               Justice, Howard's Way, Tripods, Coronation
                                 Street and Juliet
                                   Bravo. He played the voice of K9 after John Leeson
                             decided not to continue. However, he only ended
                             up playing the part during season 17 due to other
                             work commitments so creating the opportunity for
                             John Leeson to return for a further season before
                             K9 left the series. He has also been involved in
                             radio and theatre work including The Hound of
                               the Baskerville, Julies Caesar, Romeo
                                 and Juliet, and A Midsummer Night's Dream. He can been seen reminiscing,
                             along with John Leeson, about his time as K9 in
                             the 2001 Reeltime Video "K9 Unleashed!". | 
                          
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                                   K9
                 was a mobile computer constructed by Professor Marius of the
                 medical Bi-Al Foundation. He was both a database and huge source
                 of information but also had defensive capabilities as he was
                 equipped with a laser in his nose which could be set to stun
                 or kill. Being in the shape of a dog he was very useful in his
                 ability to sneak up unawares on his foe. 
					  
					   In his
					 first encounter, with the Fourth
					 Doctor and companion Leela, K9 was to prove invaluable in helping to defeat
					 the Swarm that was attacking not only the Bi-Al Foundation but The Doctor's
					 own brain. After this encounter, Professor Marius gave K9 to The Doctor
					 as he was no longer able to keep K9 himself. From the outset it was clear
					 that K9 was a computer with a vast amount of knowledge with an even bigger
					 ego to match. 
               
                 
                   
                     
                       
                          "He's very useful; he's my own personal data bank.
                           He knows everything that I do, don't you, K9?"  
                           "Affirmative. And more, Master."  
                           (Professor Marius and K9, "The
                             Invisible Enemy") 
                        
                      
                       
                    
                  
                
               
                 
                         
                           
                             
                                 | 
                              
                             
                               | The Invisible Enemy | 
                              
                            
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                                         Nevertheless both The Doctor and Leela took an instant
                     liking to K9 and he did not object to the change in ownership
                     in fact he needed no prompting to enter the TARDIS.  
             
              Somehow the addition of a smug computerised
            dog with a well-developed sense of his own importance seemed to fit
            in with the already established team. K9 was to prove to be the perfect
            foil for both The Doctor's knowledge and arrogance, and Leela's primitive
            intuition. He also provided the necessary element of humour and he
            served as an extra 'hook' for the audience, aimed mostly at the younger
            viewers just as Leela was a 'hook' for the older male viewers. And
            of course with the success of Star Wars the same year cute robots
            were the in-thing.  
					  
					   K9 though
					 did have a tendency to break down rather a lot as demonstrated when he
					 became damaged prior to the fight against the Fendhal, thus causing him
					 to remain inside the TARDIS for the duration of that encounter. His absence
					 in a number of stories is blamed on corroded circuitry, and being unsuited
					 to the terrain in which the TARDIS took them to. Despite this he was to
					 prove to be a very useful tool. With his laser gun K9 had a tendency to
					 lead the plot into many a battle scene with many laser shots been fired
					 in all directions. 
                      
                       Despite
                     being a computer K9 had many human traits and his smugness
                     and tendency to show The Doctor up much to his annoyance.
                     Never liking to be outdone The Doctor, while losing at a
                     game of chess with K9, causes the game to be wrecked when
                     he makes the TARDIS lurch. Leela is also seen to chide The
                     Doctor for calling K9 'him' instead of 'it' something that
                     he had earlier pulled her up on. The Doctor claims that
                     he is allowed to do so as K9 is his dog for which K9 nods
                     in agreement. However, Leela is able to take advantage of
                     The Doctor and K9's love-hate relationship and when in on
                     instance when K9 disagrees with The Doctor's prophecies
                     on the future causing The Doctor to storm off in a huff
                     Leela is seen to kiss K9 on the nose. 
                      
                     
                       
                         
                           
                             
                                 | 
                              
                             
                               | The Ribos Operation | 
                              
                            
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                       K9's loyalty
                     to The Doctor is in no doubt as demonstrated in the story "The
                     Invasion of Time", where he is seen following The Doctor's
                     orders to put the Transduction Barriers, that protect Gallifrey
                     from invasion, out of action without question thus allowing
                     the Vardans to invade. Of course this turns out to be a
                     ruse so that K9 can be linked to the Matrix so as to determine
                     the Vardans point of origin and so defeat them. While he
                     was more than willing to obey The Doctor, K9 was not incapable
                     of making his own decisions. He displayed this not only
                     when he joined The Doctor, but also during his travels,
                     such as when he left the TARDIS to search for The Doctor
                     and Leela despite being ordered to remain after their arrival
                     on Pluto ("The
                     Sun Makers"). His ability to make
                     independent decisions was also seen when he decided to stay
                     on Gallifrey with Leela who he knew was very fond and devoted
                     to him. 
                      
                       When Leela
                     elects to stay on Gallifrey with one of the Chancellary
                     guards with whom she has fallen in love with K9 announces
                     that he will remain with her and so The Doctor returns to
                     the TARDIS apparently on his own and unaffected by this
                     double loss. However, it soon becomes obvious that The Doctor
                     had been secretly working on an improved model when he is
                     seen dragging into the console room a large box with 'K9
                     Mk II' printed on its side. 
                      
                     
                       
                         
                           
                             
                                 | 
                              
                             
                               | The Androids of Tara | 
                              
                            
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                       Exactly
                     how The Doctor was able to build K9 Mark II was never explained.
                     It can therefore only be assumed that he was able to obtain
                     a set of blueprints from the first K9's memory banks which
                     allowed him to build K9's duplicate. However, while similar
                     to his predecessor the new version had many enhancements
                     including better mobility and the ability to sense danger
                     and respond to ultrasonic signals. He retained, however,
                     that all-knowing smugness, and with the arrival of Romana this meant a whole new set of challenges
                     for The Doctor who had to prove himself to both of them
                     (Although The Doctor allegedly also had a habit of losing
                     K9; according to Romana mid-way through their search for
                     the Key to Time, with the amount of time he’d spent
                     lost before The Doctor could recover him K9 by now would
                     have to be the single oldest coherent matter in the universe,
                     although she may have been exaggerating out of frustration
                     ("Heart
                     of TARDIS")). 
                      
                       K9 assisted
                     them both during their search for the Key of Time and it
                     was during this time that all three of them were all trying
                     to outdo each other, and if it meant The Doctor could be
                     proved wrong, then K9 and Romana always joined forces against
                     him, even as their shared loyalty to him was unquestioned.
                     K9 Mk II also had much more involvement than his predecessor,
                     and his abilities were used to the full (A particularly
                     amusing example of this being his ‘duel’ with
                     a robotic parrot belonging to the ruthless Captain in "The
                     Pirate Planet"). He was seen carrying out many varied
                     tasks including tracking, flying aircars as well as fighting,
                     rescuing The Doctor and Romana out of sticky situations
                     and, in the "The
                     Armageddon Factor", he acted
               as a Trojan Horse for a very small Doctor and Drax. 
                
               
                 
                   
                     
                       
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                         | The Creature from the Pit | 
                        
                      
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                Most of K9's charisma came from his relationship with The Doctor, matching The Doctor’s technical expertise and general knowledge while  providing Leela with more relatable explanations and providing Romana with  someone else she could talk to.
               He was perhaps the only one who could undermine The Doctor's 'infallibility'
               with one smug comment and for an automaton with no capacity for
               emotional responses, K9 certainly had his fair share of feelings.
               These ranged from an eager desire to accompany The Doctor and
               Leela in the exploration of the mysteriously-inhabited Pluto ("The
               Sun Makers"), regret at his perceived failure to protect
               The Doctor ("Festival
               of Death"), calls for assistance
               after he was left drifting in a lake ("The Androids of Tara"),
               and even apparent frustration with the TARDIS itself for not being
               able to speak ("The Invasion of Time"). This is what
               gave him his personality, and what made him a likeable character
               and a huge success. 
                
                 Although his mechanical nature still gave him crucial advantages, such as when he spent two thousand years on the planet Aoris during a war between its past and future - once to disarm a bomb planted in the past to destroy a future military bunker and a second time to essentially inspire a cult that would aid The Doctor and Romana in the future - ("The Paradox Planet/Legacy of Death"), K9 was subject to various power depletions and disorders. One unusual occasion saw him somehow contract laryngitis ("Destiny of the Daleks"), resulting in his voice changing significantly for a year. These malfunctions included being nearly melted down, his circuits nearly overloading due to exposure to the higher dimensions ("Tomb of Valdemaar"), and being shorted out when he was accidentally immersed in the English Channel ("The Leisure Hive"). A particularly damaging occurrence seemed to be when he was trapped in a dimensional rift and briefly possessed by The Repulsion, a being of pure death that hated all life and sought access to this universe ("Festival of Death"). Shortly after these events, K9s latest repair saw The Doctor note that he would now need to be recharged every two hours, due to a chronic power depletion problem ("Meglos"). K9 became damaged even further when he has his head knocked off by a marauding Marshman ("Full Circle"), and although he rallied in time to lead a resistance against the vampiric Three Who Rule while The Doctor defeated the Great Vampire ("State of Decay"), later damage caused by the Time Winds surrounding the Gateway between E-Space and N-Space prevented him from continuing with The Doctor. K9 therefore elected to stay behind in E-Space with Romana ("Warriors' Gate"). 
                
               
                 
                   
                     
                       
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                         | Full Circle | 
                        
                      
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                 K9's departure
               from the television show had many reasons behind it. Mainly it
               was felt he was being used too often as a rescue device, his function
               to provide humour was no longer required and with the introduction
               of Adric the need for a device to explain proceedings
               was greatly reduced. His departure from the show, however, caused
               a huge outcry,
               with many fans venting their fury towards current producer John
               Nathan-Turner. So much so that in 1981 the BBC agreed to make
               a Christmas Special. Titled "K9 and Company: A Girls Best
               Friend" this pilot, of an envisaged series, involved a K9
               Mark III being sent to Sarah
               Jane Smith as a present from The
               Doctor. The two of them became involved battling black magic and
               the occult in a small English village. The planned series was
               never produced past the pilot but it did allow for K9 Mark III
               to make a brief appearance in Doctor Who proper in the
               1983, 20th anniversary story "The
               Five Doctors", where
               he attempted to warn Sarah of great danger just before she finds
               herself transported
               to the Death Zone on Gallifrey and reunited with the Third
               Doctor and The
               Brigadier, along with fellow companions Susan,
               Tegan
               Jovanka and Turlough,
               and the First,
               Second               and
               Fifth               Doctors.
               He also aided Sarah when investigating the activities of the mysterious
               Remote
               (“Interference
               Book One” and “Interference
               Book Two”), during which he and Sarah encountered the Eighth
               Doctor. 
                
               
                 
                   
                     
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                       | The Five Doctors | 
                      
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                 As later
                 revealed in the novels, K9 Mark II was eventually restored to
                 his original universe when Romana returned to Gallifrey and
                 was elected President of the High Council, subsequently working
                 with Mark I to find information about the missing House of Lungbarrow
                 - The Doctor’s old family home ("Lungbarrow")
                 - as well as aiding Leela, Romana and current companion Charley
                 Pollard when they attempted to rescue The Doctor from Rassilon’s
                 attempts to turn him into a weapon against an ancient race ("Zagreus"),
                 both K9s working with Romana and Leela against the ancient Gallifreyian
                 Imperiatrix known as Pandora, who manifested using the form
                 of Romana’s first incarnation. Although Mark I was destroyed
                 during the Gallifreyian civil war against Pandora, Mark II briefly
                 returned at the conclusion of "The
                 Gallifrey Chronicles", where it was revealed that he
                 was transported into the TARDIS prior to Gallifrey’s destruction
                 with orders to kill The Doctor in an attempt to defeat Grandfather
                 Paradox - The Doctor’s corrupted future incarnation
                 and leader of the attack on Gallifrey - only to be trapped in
                 a distant part of the TARDIS. Even after the TARDIS regenerated itself when The Doctor had to expend its energy to stop the Faction, the architectural systems left K9 trapped behind a wall so that he couldn’t complete his mission.
  
  
    
      
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        Tenth Doctor Classic Companions 
          (John Dorney, Lizzie Hopley and Roy Gill) | 
       
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  Eventually, K9 escaped his confinement when the TARDIS was damaged by an exploding cold fusion generator that The Doctor had contained within his ship to stop it destroying London. The wall keeping K9 confined having cracked, the now-amnesiac Doctor let him out while investigating the damage, but although K9 initially tried to kill The Doctor, he changed his mind when he learned that The Doctor at least partly saved Gallifrey
                 by downloading the Matrix into his subconscious mind (Albeit
                 at the cost of his own memories as he was forced to erase them
                 to create room), K9 noting with satisfaction that ‘The
                 Doctor-Master never loses’. The Doctor subsequently sent K9 to contact the mysterious Madam Xing ("Halflife")
                 at the conclusion of the novel - most likely to seek a means
                 of transferring the dormant Time Lord memories in his mind before restoring his own memories - and this K9 was next reported to be involved with Gallifrey again, the Time Lords restored and The Doctor back to normal. Following the apparent destruction of Gallifrey during the Time War ("The End of Time" and "The Day of The Doctor"), The Doctor was reunited with this K9 in his tenth incarnation when responding to an unusual distress call, leading to him discovering K9 at the heart of a dimensional anomaly ("Tenth Doctor Classic Companions"). Working with the Tenth Doctor, K9 helped a version of Leela stop a twisted alternate version of The Doctor from a fairy tale realm ("Splinters"), rescued Nyssa from a Time War criminal using fragments of Matrix technology as a fake psychotherapy treatment ("The Stuntman"), and prevented Axos ("The Claws of Axos") escaping its time loop prison ("Quantum of Axos"). After Axos was defeated, The Doctor left K9 with his seventh incarnation’s old companion Ace as she had assisted in the latest struggle, reasoning that the two would make a good team to deal with further Time War fallout on Earth.
                  
                  
                 
                   
                     
                       
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                         | School Reunion | 
                        
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                   K9 Mark
                     III returned to the television series when he aided Sarah
                     and the Tenth
                     Doctor in defeating the alien goings on in
                     a local school ("School
                     Reunion"). Although he
                     was forced to sacrifice himself to defeat The
      Krillitane invasion, The Doctor left Sarah with a rebuilt version of
                     K9 that retained the original’s databanks and memories
                     while providing Sarah with various new tools, including
                     a ‘sonic lipstick’, while also possessing such
                     new features as the ability to teleport. Due to copyright
                     debate, K9 Mark IV was initially absent from The Sarah Jane Adventures, as he was currently operating ‘outside’ of
                     time to negate an artificially created black hole. Despite
                     this, he has returned to aid Sarah on two occasions, helping her to reprogram
                     the renegade ‘Mr Smith’ - an alien computer
                     who had turned against Sarah when his original programming
                     was activated ("The Lost Boy") - and subsequently
                     providing the reprogrammed Mr Smith with the TARDIS base
                     code, allowing Mr Smith to connect the TARDIS to the Cardiff
                     Rift and thus permitting The Doctor to use the Rift to tow
                     Earth back to its proper place in space and time after it
                     was ‘stolen’ by the Daleks ("The Stolen Earth/Journey's
                     End"). K9 eventually returned to Sarah's
                     life full-time when the black hole he was monitoring was
                     drained away to provide power for a crashed space ship ("The Mad Woman in the Attic"). Now living in Bannerman Road, he was able to attend Sarah's aborted wedding, during which he was reunited with the Tenth Doctor when aiding The Doctor and Sarah's friends against the Trickster ("The Wedding of Sarah Jane Smith"). A few months later, however, he left Bannerman Road to accompany Sarah's son Luke when he went to Oxford after taking his exams early ("The Nightmare Man"). He returned to Bannerman Road with Luke when Sarah was captured by Ruby White and her computer, 'Mr White'; Ruby was an alien known as a Qetesh who sought to take Sarah's life for herself and then aid subsequent alien invasions. Although Ruby was able to capture Sarah and shut down Mr Smith, Luke and K9's return allowed K9 to identify their foe and reactivate Mr Smith to help the rest of the team drive Ruby off, creating a holographic meteor shower that caused such intense emotion that it basically overloaded Ruby. At last report, K9 Mark 4 remained in Oxford, but continued to help defend Earth, with K9 Mark 2 suggesting that he would update Mark 4 on his new mission to monitor Earth for Time War fallout after he joined Ace ("Quantum of Axos").
                     
  
                     
                       
                         
                           
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                             The Wonderful Doctor of Oz 
                               (Jacqueline Rayner)  | 
                            
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                       When the Thirteenth Doctor found herself in what appeared to be the Land of Oz ("The Wonderful Doctor of Oz") after finding evidence that the Oz series had been erased from history, she returned to the TARDIS for an hour to finish building K9 Mark V to get his assistance in translating for the robot residents of this world, although K9's literal interpretation of a casual order caused him to erase his personal memory of the Oz series before The Doctor could stop him. Still otherwise functional, this new K9 accompanied The Doctor and her companions on their journey through Oz, which The Doctor eventually realised was the Land of Fiction, now under the control of L. Frank Baum, taken out of time by Missy - a female incarnation of The Master - at a point when he was writing the second Oz book, Baum believing he was just controlling an elaborate theme park. Once Missy had been driven off and Baum released from his role as Master of the Land of Fiction, Theodore, a young man from 1938 who had wandered into the TARDIS, volunteered to become the new Master himself, even using the Land's ability to rewrite reality to make himself the girl he'd always felt he truly was, renaming herself Dorothy. When Dorothy expressed doubt about her ability to maintain the Land as she felt she lacked the necessary creativity to write anything new herself, The Doctor offered to let her keep K9 to help her inventory the existing stories in the Land and write new material that way. To go along with Theodore's change, K9 chose to call himself '2-2', The Doctor particularly amused at the notion of the two being a real 'Dorothy and Toto'. 
                      
                       Throughout
                     his time with The Doctor, K9 remained irritatingly smug
                     and invariably right. He also left the show at the height
                     of his popularity, and because of this he remains a fond
                     memory.  
               
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