Twang! (a title sometimes given two or even three exclamation marks) was a comedy musical loosely based on the Robin Hood legend. On paper it had everything in its favour. The composer, Lionel Bart, had already had a major success with Oliver!, which was in its 6th year in London when Twang! opened. The cast included Barbara Windsor and Bernard Bresslaw, well-known for their appearances in the popular Carry On films, and the director, Joan Littlewood, founder of Theatre Workshop, had recently brought her production of the anti-war musical, Oh What a Lovely War, to the West End. Only the choice of designer was surprising. Though regarded as Britain's leading theatre designer in the mid-20th century, Oliver Messel's lavish, painterly style was beginning to fall out of favour in the 1960s, and he was associated with ballet and opera not with knockabout musicals.

As it turned out, Messel was the one member of the production team to receive favourable reviews. After a troubled pre-London tour during which Joan Littlewood left the show, Twang! opened at the Shaftesbury Theatre and was savaged by the critics who found the plot poor, the script excruciatingly unfunny, and the acting flat. Messel's designs were pronounced the night's real pleasure. He created an amusing fantasy world where characters like Maid Marian dressed in medieval costumes made from 1960s fabrics.