The couple were hired after the war by
the Rank Organisation to run
Gainsborough Studios. They disapproved of the
Gainsborough melodramas which had been the studio's major successes for several years, and switched production to a broader range of more "realistic" films with mixed results. Box made 36 films at Gainsborough, which was merged into the Rank Organization in 1949. It has been argued Box's overexpansion "killed" Gainsborough. In 1951 Box founded his own production company
London Independent Producers with
William MacQuitty. Box was part of a consortium that launched the ITV franchise,
Tyne Tees Television in 1959. In the late 1950s Box signed a deal to make nuermous low budget films for the Rank Organisation. In September 1959 Box announced he was quitting filmmaking due to medical advice. In December 1959 Rank announced Sydney Box Associates would make a series of films for the company including
Love Birds starring Brian Rix,
Not in the Book produced by Norman Williams and scripted by Peter Blackmore from Arthur Watkyn’s play,
No Concern of Mine from Jeremy Kingston's play,
Milk and Honey from Philip King’s play:
Watch It, Sailor! also based on a Philip King play,
See No Evil an original by Jimmy Sangster, and
Time to Kill another original by Leigh Vance. Some of these films would be made by other companies. It has been argued he was allowed to make "far too many movies" for Rank. According to Sue Harper and Vincent Porter: Box was a skilled entrepreneur who was able to raise regular loans from the NFFC and to encourage others' talents. According to his assistant David Deutsch, he provided, more effectively than anyone he had ever known, 'the right environment for creative people to work, welcoming, encouraging and subtly influencing'. Box’s position as an outsider—a socialist of sorts, a realist by instinct, and a feminist by default—meant that he became increasingly excluded from the meritocracy. He lacked a strong visual sense, but this was supplied by Muriel Box, whose lively inventiveness was accompanied by an uncompromising sexual radicalism, which pleased her but not the distributors or the audiences. ==Selected filmography==