The Third Doctor underwent his regeneration into the Fourth Doctor as a result of the radiation poisoning he suffered after prolonged exposure to the Great One's highly unstable web of Metebelis crystals. (TV: Planet of the Spiders [+]Robert Sloman, Doctor Who season 11 (BBC1, 1974).) He subsequently spent approximately a decade drifting through the Time Vortex, his body dying of the radiation, (PROSE: Love and War [+]Paul Cornell, Virgin New Adventures (Virgin Books, 1992).) until the TARDIS "brought [him] home" to the UNIT HQ laboratory. (TV: Planet of the Spiders [+]Robert Sloman, Doctor Who season 11 (BBC1, 1974).)
History[]
Anticipation[]
While living on Gallifrey, there was a rumour that the First Doctor was able to glimpse his first seven regenerations during a game of Eighth Man Bound. (PROSE: Christmas on a Rational Planet [+]Lawrence Miles, Virgin New Adventures (Virgin Books, 1996)., Lungbarrow [+]Marc Platt, adapted from Lungbarrow, Virgin New Adventures (Virgin Books, 1997).)
During an encounter with the Eighth Doctor, the Third Doctor was told that he "[would] end [his time] by [his] own choice, in a noble cause". (PROSE: The Eight Doctors [+]Terrance Dicks, BBC Eighth Doctor Adventures (BBC Books, 1997).)
The Third Doctor began to regenerate after he fell off a roof during a struggle with the Nurazh. The Nurazh attempted to take over the dying Doctor's mind, but was unable to cope with two different versions of the Doctor co-existing at the same time and perished, healing the Doctor back to his third incarnation. (PROSE: The Touch of the Nurazh [+]Stephen Hatcher, Short Trips: Monsters (Short Trips short stories, 2004).)
The regeneration[]
During a visit to Metebelis III, the Doctor took a Metebelis crystal, which he eventually gave to Jo Grant as a wedding gift, (TV: The Green Death [+]Robert Sloman, Doctor Who season 10 (BBC1, 1973).) not knowing that the crystal was the "perfect crystal" needed by the Great One of the Eight Legs to increase her mental powers to infinity by using a web of the crystals in a plot for universal domination. After Jo returned the crystal to UNIT HQ, the Eight Legs launched an attack to retrieve the crystal for the Great One. On the advice of his old mentor, K'anpo, the Doctor elected to return the crystal to the Great One, knowing it would lead to her destruction, as well as his own. Returning to Metebelis III, the Doctor was irradiated by the Great One's web of crystals as he gave the crystal to her. After she was destroyed by her inability to harness the limitless power of the crystals, the Doctor limped back to the TARDIS, but "got lost in the Time Vortex" (TV: Planet of the Spiders [+]Robert Sloman, Doctor Who season 11 (BBC1, 1974).) for ten years, as the radiation slowly ate away at his body. (PROSE: Love and War [+]Paul Cornell, Virgin New Adventures (Virgin Books, 1992).)
While he did end up having some adventures even in his weakened state, (PROSE: Ancient Whispers [+]Brian Willis, Short Trips: The Centenarian (Short Trips short stories, 2006)., The Loneliness of the Long-Distance Time Traveller [+]Error: Code 2 - no data stored in variables, cache or SMW.) the effects eventually became so severe that he could not even reach the TARDIS console, and was doomed to simply wait until the TARDIS landed of its own accord. (PROSE: Love and War [+]Paul Cornell, Virgin New Adventures (Virgin Books, 1992).) Eventually, the TARDIS brought him "home" to UNIT HQ three weeks after he left from their perspective, and he promptly collapsed in the UNIT HQ laboratory. He managed to say goodbye to Sarah Jane Smith and Brigadier Alistair Gordon Lethbridge-Stewart before expiring. However, K'anpo's latest incarnation, Cho-Je, managed to give the Doctor "a little push" to begin the regeneration process, and the Doctor's face faded into his next incarnation. (TV: Planet of the Spiders [+]Robert Sloman, Doctor Who season 11 (BBC1, 1974).)
Immediate aftermath[]
Info from Robot [+]Terrance Dicks, Doctor Who season 12 (BBC1, 1974-1975). needs to be added
Legacy[]
When she reunited with the Third Doctor in the Death Zone, Sarah Jane Smith commented on him being in his third incarnation after she had seen him regenerate into the Fourth Doctor, with the hand movements she used to describe him cluing the Doctor into his next incarnation having noticeable "teeth and curls". Once he realised what she was trying to say, the Doctor clarified to her that she was meeting him before his regeneration, which was yet to happen for him. (TV: The Five Doctors [+]Terrance Dicks, Doctor Who 20th Anniversary Special (Public Broadcasting Service, 1983).)
In other realities[]
Due to interference caused by Faction Paradox to the Eighth Doctor's time stream, the circumstances of the Third Doctor's regeneration were altered so that he regenerated on Dust during the War in Heaven when he was shot in the chest by Magdelana Bishop due to the danger she felt that he brought to her world. When Sarah found him, the Doctor had already begun regenerating as she dragged him back to the TARDIS, where he completed his regeneration, but knew something was wrong with the situation. Mother Mathara believed there would be no substantial difference in the timeline until the Eighth Doctor's time. (PROSE: Interference - Book Two [+]Lawrence Miles, BBC Eighth Doctor Adventures (BBC Books, 1999).) The Eighth Doctor eventually forced the universe to choose one of the two timelines to be real when he ended the the Faction Paradox invasion of Gallifrey, (PROSE: The Ancestor Cell [+]Peter Anghelides and Stephen Cole, BBC Eighth Doctor Adventures (BBC Books, 2000).) with a history book of the universe recounting that the Third Doctor regenerated after the battle with the Eight Legs. (PROSE: The Whoniverse [+]George Mann and Justin Richards, BBC Books (2016).)
Behind the scenes[]
An alternative regeneration for the Third Doctor occurred in the stage play Doctor Who and the Daleks in Seven Keys to Doomsday [+]Terrance Dicks, 1974., which premiered after Planet of the Spiders [+]Robert Sloman, Doctor Who season 11 (BBC1, 1974). and directly before TV: Robot [+]Terrance Dicks, Doctor Who season 12 (BBC1, 1974-1975).. As both Jon Pertwee and Tom Baker were not available for the production, Trevor Martin was cast as a new incarnation of the Doctor. The play began with Martin obscuring his face while wearing a wig and costume indicating that he was the Third Doctor, not unlike Seventh Doctor actor Sylvester McCoy's portrayal of the Sixth Doctor in Time and the Rani [+]Pip & Jane Baker, Doctor Who season 24 (BBC1, 1987).. He would then collapse on stage, and two "audience members" would rush from their sets to help him. An image on a rear-projected screen would then show Pertwee's face turning into Martin's. As the lights turned back on, Martin would be wearing a new costume with his natural hair. As he awoke, it was revealed that the audience members were his new companions, Jenny Wilson and Jimmy Forbes, who had been sitting in the audience as a trick of immersion.
