Cooper was a pioneer in writing for the broadcast media, becoming prolific in both radio and television drama. His early successes included radio dramatisations of Dickens'
Oliver Twist,
William Golding's
Lord of the Flies and
John Wyndham's science fiction novel
The Day of the Triffids. Wyndham wrote to Cooper congratulating him after the first broadcast. On television he adapted Simenon's
Maigret detective novels from the French, which became the major hit of the day (1960–61) starring
Rupert Davies as the pipe-smoking sleuth in over 24 episodes, for which he won the Script Award in 1961 of the Guild of Television Producers, which subsequently became
BAFTA. He also adapted four
Sherlock Holmes stories,
Ernest Hemingway's
For Whom the Bell Tolls (1965),
Les Misérables, Flaubert's
Madame Bovary and
Evelyn Waugh's trilogy of novels
Sword of Honour (1967) for
Theatre 625. the first and only American production, starring
Martyn Green, was syndicated to public stations in 1981 by the
National Radio Theater of Chicago. Also of note are
Unman, Wittering and Zigo (1958) in which a young teacher finds his predecessor has been murdered by the boys in his class and
The Long House (1965). "Out of the Crocodile" ran at the Phoenix Theatre in 1963-64 starring
Kenneth More,
Celia Johnson and
Cyril Raymond.
"The Spies are Singing" was presented at the
Nottingham Playhouse in 1966, starring the theatre's Artistic Director
John Neville. Many of his plays were later adapted for both stage and television.
Unman, Wittering and Zigo,
Seek Her Out, in which a woman (played by
Toby Robins) witnesses an assassination on the
London Underground and becomes the next would-be victim of the perpetrators; and
The Long House were parts of an unrelated trilogy of plays by Cooper broadcast on
BBC2's
Theatre 625 during the summer of 1965. He also wrote
The Other Man a television drama starring
Michael Caine,
Siân Phillips and
John Thaw and first broadcast on
ITV in 1964.
Everything in the Garden was first performed by the
Royal Shakespeare Company in 1962 at the Arts Theatre, London; in 1967, an American adaptation by
Edward Albee, was first performed in 1967 at the
Plymouth Theatre,
New York City, and dedicated to Cooper's memory. His last play was
Happy Family was first presented at the
Hampstead Theatre in 1966 starring
Wendy Craig; it then transferred to the
West End with
Michael Denison,
Dulcie Gray and
Robert Flemyng. A revival in 1984 directed by
Maria Aitken opened in Windsor and transferred to the
Duke of York's Theatre in the West End, starring
Ian Ogilvy,
Angela Thorne,
James Laurenson and
Stephanie Beacham. ==Death==