Regional repertory theatre companies like the Birmingham Repertory Theatre were committed to producing a wide variety of drama for local audiences. From the early years of the 20th century, through their heyday in the middle decades of the century, they provided a training ground for young actors. In 'weekly rep', actors would make their way through a wide range of roles from farce to Shakespeare each season. This stood them in excellent stead for going on to work in the West End, on television, and in film.
Although the repertory companies also liked to work with local writers, producing new plays, a classic comedy like Oscar Wilde's The Importance of Being Earnest would provide a strong box office success, enabling them also to stage more innovative work. In this photograph from the Birmingham Rep's 1959 production, you can see two actors who went on to substantial screen careers: Thelma Barlow (who played in Coronation Street for 26 years) is Gwendolen Fairfax, and Ian Richardson (star of many films and TV series) plays Jack Worthing.