Complex sentence: It was directed by Karel Reisz and produced by Leon Clore from a screenplay by David Mercer, based on his 1962 television play for BBC Television, the leading role at that time being played by Keith Barron.
Split into simpler sentences: It was directed by Karel Reisz and produced by Leon Clore from a screenplay by David Mercer. The play had previously appeared on BBC Television, the leading role at that time being played by Keith Barron.