Peter Davison Peter Davison ( born Peter Malcolm Gordon Moffett ) portrayed the fifth incarnation of the Doctor from 1981 to 1984 , beginning with the conclusion of " Logopolis " and ending with " The Caves of Androzani " . He reprised the role for the 1993 Children in Need special , " Dimensions in Time " and again for the 2007 Children in Need special , " Time Crash " . He has also voiced the Doctor for numerous " Doctor Who " audio dramas for Big Finish Productions . Davison is also well - known for his roles as Tristan Farnon in " All Creatures Great and Small " . Davison was born Peter Moffett in London . His father was originally from Guyana . He studied at the Central School of Speech and Drama and appeared in several stage productions and some minor television roles before he got his big break in 1978 . His performance as the ne ' er - do - well Tristan Farnon in " All Creatures Great and Small " made him a household name . He married American actress Sandra Dickinson in the same year , but they divorced in 1994 . He and Dickinson had previously appeared together in the three - part story " A Man For Emily " in the ITV Sci - Fi series " The Tomorrow People " ( 1975 ) and together composed and performed the theme tune to ITVs " Button Moon " , a lunchtime children ' s programme broadcast in the 1980s . Davison made a cameo appearance alongside Dickinson as the Dish of the Day in the BBC television version of " The Hitchhiker ' s Guide to the Galaxy " ( 1981 ) , whose producers considered it humorous for an actor known for playing a veterinary surgeon to appear as a cow . Davison also appeared in some British sitcoms , including " Holding the Fort " and " Sink or Swim " during his time as " Doctor Who " and later " Fiddlers Three " and " Ain ' t Misbehavin " , as well as appearing in dramatic roles . " Doctor Who " career . In 1981 , Davison signed a contract to play the Fifth Doctor for three years , succeeding Tom Baker ( the Fourth Doctor ) . Twenty - nine at the time of his first appearance in the series , Davison was the youngest actor to have played the Doctor in the series or in any BBC - sanctioned " Doctor Who " production . In 2010 , he handed over this distinction to Matt Smith , who was twenty - six at the time of his début . Coincidentally , several of Davison ' s stories were directed by Peter Moffatt ( only a slight variation of Davison ' s birth name , Peter Moff " e " tt ) , and , on the 2008 DVD release of " The Five Doctors " , Davison recalls friends thinking he not only starred in the show , but directed it as well . Attracting such a high - profile actor was as much of a coup for the programme ' s producers as getting the role was for him , but he did not renew his contract because he feared being typecast . Reportedly , Patrick Troughton ( who had played the Second Doctor ) had recommended to Davison that he leave the role after three years , and Davison followed his advice . In 2013 , Davison also wrote , directed , and starred in " The Five ( ish ) Doctors Reboot " , a comical film released on the Red Button in which he , alongside Colin Baker and Sylvester McCoy , attempts to appear in the 50th anniversary " Doctor Who " episode , " The Day of the Doctor " . After " Doctor Who " . After leaving " Doctor Who " , he continued to appear occasionally on television , including an appearance on the American show " Magnum , P . I . " ( following the lead of Tom Baker who similarly made a high - profile US TV appearance in " Remington Steele " after leaving the series ) . It was not until 1986 that Davison worked on another very popular series . He played Dr Stephen Daker , the ingenuous hero of " A Very Peculiar Practice " , written by Andrew Davies . The surreal comedy - drama was revived several years later as a one off TV film " A Very Polish Practice " . Davison also played the lead in another BBC production , " Campion " , a series based on the period whodunnits of Margery Allingham . This , and the opportunity to play Tristan Farnon again in 1985 and 1990 in the revived series of All Creatures Great and Small , kept Davison busy until the early 1990s . He also worked on several occasions with BBV Productions , co - starring with several other former Doctors in the SF film " The Airzone Solution " and he reprised the Fifth Doctor for the controversial " Dimensions in Time " special . In 1999 he appeared as the outgoing headteacher in " Hope And Glory " . He appeared with Mark Gatiss in " Doctor Who " spoof , " The Kidnappers " , in which he appeared as himself ( this skit was later included in the The Beginning DVD box set ) . In 1995 he presented " Heavenly Bodies " a six - part series about astronomy , broadcast on BBC1 . This led to him being featured on the cover of " Practical Astronomy " magazine ( Volume 1 , number 5 , dated March 1995 ) . It was not until 2000 that he returned in another major role , that of David Braithwaite in " At Home with the Braithwaites " , which ran for four seasons on ITV . More recently , he starred in the television series " The Last Detective " ( based on the Dangerous Davies novels by Leslie Thomas ) ( 2003 - 2007 ) and " Distant Shores " ( 2005 ) for ITV , the latter where he coincidentally also played a doctor . In 2011 , he took a major recurring role on " Law & Order : UK " . His daughter with Dickinson , Georgia Moffett , had a child while still in her teens , making Davison a young grandfather . Georgia auditioned for the role of Rose Tyler in " Doctor Who " s 2005 revival and also auditioned for a role in the 2008 episode , " The Unicorn and the Wasp " . She was cast as Jenny , the titular character in the Series 4 episode " The Doctor ' s Daughter " , which aired several months after her father ' s appearance in " Time Crash " . She also voiced a different character for the animated serial , " Dreamland " . She married the Tenth Doctor ' s actor , David Tennant , on 30 December 2011 , meaning Davison is Tennant ' s father - in - law ( a fact played up for laughs in " The Five ( ish ) Doctors Reboot " ) . Davison was also a regular in the BBC Radio 4 comedy series " Rigor Mortis " . In fiction . Peter Davison exists within the Whoniverse . During an adventure in which the Eleventh Doctor found himself in the " real world " where his adventures are the subject of a TV series called " Doctor Who " , he states that he once saved the actor from a Krynoid back in his own universe , noting that he thought he looked familiar . ( COMIC : " The Girl Who Loved Doctor Who " ) Davison also filmed a skit for an Australian news station depicting Davison and the Fifth Doctor being interviewed about the cast change from Tom Baker . This is not seen at " TARDIS wikia " as a valid source for writing .