Here's a look at the actors who where nearly Who.
Hugh David was the first actor lined up for the role of Doctor Who. But when Verity Lambert was appointed producer of the series, she felt that he was too young to play the old man she envisaged. He still made his mark on the series as director of two Patrick Troughton stories, 'The Highlanders' and 'Fury from the Deep'.
'Doctor Who' producer Verity Lambert eventually selected William Hartnell to star in the series, but one name she had on her shortlist was respected theatre actor Cyril Cusack, pictured here as Becket in the 1964 production of TS Eliot's 'Murder in the Cathedral'.
Verity Lambert also considered Leslie French to play the Doctor. Though he didn't get the part, he appeared in the 'Doctor Who' 25th anniversary adventure 'Silver Nemesis' as an ill-fated astrologer. He's pictured here as Mr Woodhouse in a 1960 adaptation of Jane Austen's 'Emma'.
Pictures and text from the Beeb's Changing Face of Doctor Who, here.
And here's Billy, the man who got the job, from shillpages, here.