Doctor Who – The Ultimate Adventure Doctor Who – The Ultimate Adventure Doctor Who – The Ultimate Adventure was a 1989 stage play written by Terrance Dicks, based on the long-running British science fiction television series "Doctor Who". The play was staged at twenty theatres around Britain, commencing 23 March 1989. It initially starred Jon Pertwee (who had played the Third Doctor in the series) as the Doctor. On 29 April Pertwee was ill, so understudy David Banks, who portrayed the Cyber Leader in the series from "Earthshock" onwards, played the Doctor for the matinee and evening performances. Pertwee continued in the role until 3 June
The Doctor (Doctor Who) that time was that regeneration had turned back the Doctor's clock, making him younger both in appearance and in biological age. Since the Doctor's age had never previously been given, 450 Earth years became a starting point onto which further years would be progressively added as the series continued and the character lived out his further incarnations. The Third Doctor implied in "Doctor Who and the Silurians" (1970) and in "The Mind of Evil" (1971) that he had a lifetime that covered "several thousand years". While the Doctor's age has never been a known quantity, these numbers are the most