In its early decades, Doctor Who tended to cast character actors in guest roles – familiar faces with well-worn personas, usefully deployed to flesh out stock figures. File Catweazle star Geoffrey Bayldon under ‘wizardly’, the perpetually frowning Cyril Shaps under ‘harried’, and Bernard Horsfall under ‘tersely rugged’. Excellent, unfussy actors, who disappeared into their roles.
Headline guests weren’t actively sought but still occasionally appeared, thanks to Doctor Who’s anthology-style format – with the serials requiring a steady roster of supporting actors and a relatively low commitment, time-wise. 1964’s Marco Polo featured the show’s first promoted guest star, with actor Mark Eden, as the Venetian explorer, placed prominently on Doctor Who’s first ever Radio Times cover.
In the years that followed, star names tended to be film actors on the wane. George Coulouris, once a notable feature of Orson Welles’ Citizen Kane, accepted the thankless role of Arbitan in The Keys of Marinus (1964). Horror-movie regular Michael Gough added star wattage to The Celestial Toymaker (1966), acting as de-facto lead for a fortnight while William Hartnell was away on holiday. And the prolific Canadian actor Robert Beatty brought his trademark military-man persona to General Cutler in The Tenth Planet (1966), just ahead of appearing in 2001: A Space Odyssey for Stanley Kubrick.