|The Sarah Jane Adventures character|
|Affiliated||Sarah Jane Smith|
|Home era||Early 21st century|
|First appearance||Revenge of the Slitheen|
|Last appearance||The Man Who Never Was|
|Portrayed by||Daniel Anthony|
Clyde Langer is a fictional character played by Daniel Anthony in the British children's science fiction television programme The Sarah Jane Adventures. He first appears in the second and third episodes, Revenge of the Slitheen, and is a replacement for the character Kelsey Hooper, who had been featured in the series premiere.
Within the narrative of the series, Clyde is a friend of alien investigator Sarah Jane Smith (Elisabeth Sladen) and her son Luke (Tommy Knight), and helps the Smiths to investigate alien activity in and around London. Through his friendship with Luke, popular Clyde becomes more confident in his own intelligence and artistic ability, staying on at sixth form, while also helping Luke—a genetically engineered boy genius—better adapt to the cultural norms of being a teenager. From the show's second series onwards, Clyde's storylines in particular have suggested romantic tension with his fellow alien investigator, classmate and friend Rani Chandra (Anjli Mohindra).
 Character history
Born in Halesowen, but moved down to London after his father having run off with his aunt to Germany when he was ten. Clyde moved to the same catchment area as Maria and Luke sometime before Revenge of the Slitheen, and like them was a new student at the local school. Clyde lives with his mother, and agrees with Maria that he, like her, is happier for his parents to live apart rather than to argue. Clyde appears to put a lot of value in appearing "cool", and is a bit of a troublemaker. He initially finds Maria and Luke strange — especially Luke. However, Clyde is not without his tender side, and encourages Sarah Jane to allow Luke to call her "Mum", suspecting that this is what she really wants.
Introduced in the first episode of series one, Revenge of the Slitheen, Clyde discovers that aliens exist, follow Maria Jackson (Yasmin Paige) into the school technology block and seeing several Slitheen (including a child Slitheen) whom he sees change out of their disguises. While Sarah Jane was annoyed to have another person depending on her she eventually warmed to Clyde when he proved helpful in figuring out the Slitheen's weakness and in defeating the family. Clyde forms a friendship with the socially inept but intellectually brilliant Luke Smith at this time, helping him attempt to function as an average boy in social situations. In Warriors of Kudlak, Luke asks Clyde to explain about girls.
In The Lost Boy, Clyde is trapped inside Mr Smith to stop him from exposing the computer as a villain and to use as a hostage. From within Mr Smith however, Clyde managed to surprise the computer by sending messages to another computer from within him.
He is banned by the Judoon from extraterrestrial travel as punishment for interference in their work in Prisoner of the Judoon. Despite having been grounded, Clyde finds himself briefly transported to an alien world in Death of the Doctor but is not caught by the Judoon. He subsequently becomes nobility of an unspecified planet when its ruler, Gavin, creates him Lord Clyde in recognition of Clyde's assistance in Gavin's succession which simultaneously saved the whole of humanity. The Empty Planet.
During The Wedding of Sarah Jane Smith, Clyde is temporarily charged with artron energy when he comes in contact with the TARDIS while it is attempting to penetrate a time trap created by the Trickster, allowing him to briefly hurt the Trickster long enough for the Tenth Doctor (David Tennant) to communicate with Sarah. The Eleventh Doctor (Matt Smith) later uses the Artron energy apparently still in Clyde to transport across time and space in Death of the Doctor.
In The Curse of Clyde Langer, Clyde finds himself isolated from his friends and family and living in the streets after being splintered from a totem pole. Hetocumtek, an extraterrestrial warrior god, resides in the trap, finally making his escape plan as he places a curse on Clyde's name. New recruit Sky Smith (Sinead Michael), who is not affected by the curse, is able to realise the problem and helps Sarah Jane and Rani break the curse before helping him destroy Hetocumtek.
 Alternate timelines
||This article or section may fail to make a clear distinction between fact and fiction. (October 2009)|
In Whatever Happened to Sarah Jane?, a mysterious being known as the Trickster changes the universe to that Sarah Jane had died as a child. Consequently, Clyde forgets about friend Maria Jackson and Luke, who temporarily cease to exist.
Clyde is mentioned for the first time in the Doctor Who episode "Turn Left". The episode sees a monster belonging to the Trickster's Brigade creating an alternate timeline where the series' hero the Doctor never meets companion Donna Noble, and is thus killed. In this new timeline, Clyde is said to have been killed along with Sarah Jane, Maria, Luke, and medical student Martha Jones while stopping the events of the Doctor Who episode "Smith and Jones".