Alexander Armstrong :: Character Guides

Mr Smith is a fictional extraterrestrial computer voiced by Alexander Armstrong which appears in the British children's science fiction television series, The Sarah Jane Adventures, with further minor appearances in the final two episodes of the fourth series of Doctor Who. It is installed in the attic of Sarah Jane Smith's home, and is used to hack into other systems; Sarah Jane asserts that it can hack "into anything". It first appeared in "Invasion of the Bane" the 2007 New Year's day special and has appeared in all stories to date.
Unlike Sarah Jane's sonic lipstick and scanner watch, Mr Smith was not given to her by the Doctor, but is a Xylok, a crystal race which crashed to Earth as a meteor and were trapped underneath the surface of the Earth for thousands of years until the eruption of Krakatoa freed a tiny piece of the Xylok entity. Sarah Jane was able to obtain the piece for inspection where she found it could communicate with her laptop. By doing so it was able to create Mr Smith. Mr. Smith's main screen displays a visualisation when not being used for a purpose, and behind the screen is a large mass of tangled wires.
Mr Smith is hidden behind the chimney breast in Sarah Jane's attic at 13 Bannerman Road. It reveals itself on the vocal command "Mr Smith, I need you," although it is capable of self-activation. When it reveals itself as requested a fanfare plays - apparently diegetic, as Sarah Jane comments on it in the Doctor Who episode The Stolen Earth. It can also request the attention of Sarah Jane and be heard quite clearly from her living room, a full three floors below. In "Invasion of the Bane", Sarah Jane is somewhat unwilling to allow either Maria Jackson or the young boy they rescued into her attic to see Mr Smith. However, after Kelsey Harper sneaks upstairs, Sarah Jane reveals Mr Smith to them when she uses it to hack into the Bubble Shock! factory computers in order to issue a warning to Mrs. Wormwood and the other Bane.
Mr Smith is also able to create replicas of official documents for Sarah Jane's use; for example, it created the necessary documents she needed to adopt Luke and falsified news reports to explain global blackouts. According to the official website[1] Mr Smith has two access levels and Sarah Jane has only basic level clearance, as Mr Smith only allows the species that created it access to level two (although even basic level clearance has a very wide range of capabilities, so Sarah Jane is not hindered by this). It constantly scans all media, police, and other similar sources for reports of alien incursions. It also scans for celebrity gossip for its own amusement.
Mr Smith is clearly capable of conducting self-diagnostics and of extrapolating from orders given to generate information likely to be needed. In the second episode of the first series, it also warns Clyde Langer against trying to investigate its capabilities, and does so in an uncharacteristically authoritarian "voice", suggesting a darker side to its personality as it even gives a slightly menacing chuckle. In the penultimate episode, it reveals to Clyde that it is a Xylok and is working with the Slitheen to kidnap Sarah Jane's adopted son Luke. It plans to bring the Moon crashing onto the Earth by using Luke with a telekinetic energiser headset tuned to humans' natural telekinetic power which uses it to enable the user to move things with their mind. The gravitational pull of the Moon would tear the Earth apart, thereby freeing the Xylok race.
Sarah Jane unleashes K-9 to battle Mr Smith while she covertly enters a computer virus acquired by Maria's father. Thanks to K-9's attack distracting Mr. Smith, she is successful in her attempts to infect him with the virus. As Mr Smith's databanks collapse, it loses the memory of its prime objective, which Sarah Jane reaffirms is to save the Earth. Mr Smith shuts down, and the Moon returns to its regular orbit. In the episode's dénouement, Sarah Jane promises that when Mr Smith is rebooted its prime objective will be "to safeguard the Earth", meaning it will resume its normal role in the series.
Mr Smith makes an appearance in the Doctor Who episode "The Stolen Earth" along with Sarah Jane and Luke, helping the two of them to contact other past companions such as Jack Harkness and Martha Jones. When Harriet Jones asks them to help her send a signal to the Doctor, Mr Smith hacks into every telephone line on Earth, allowing the entire world to phone the Doctor - currently using Martha's old mobile phone - simultaneously, thus breaking through the barrier that Davros and the Daleks had erected around Earth. Mr Smith further assists the team in the finale episode "Journey's End" with the help of K-9 and Torchwood Three, by creating a lasso of temporal energy around the TARDIS to tow Earth back to its proper location in space.
Since the reboot his visualisation has changed into a distorted, liquid like, version of his original one and some of his controls have been slightly altered. He also appears to have gained a sense of humour.