with 7 episodes premiered on Invalid Date

with 26 episodes premiered on January 7, 1961

"The Frighteners," "Girl on the Trapeze" and the first twenty minutes of "Hot Snow" are the known episodes to exist of the first season. All the other episodes of season one were destroyed by the BBC… see more

with 26 episodes premiered on September 29, 1962

with 26 episodes premiered on September 28, 1963

with 26 episodes premiered on October 2, 1965

with 24 episodes premiered on January 14, 1967

with 33 episodes premiered on September 25, 1968