This poster was designed for London Transport in 1929 by the calligrapher, graphic designer, textile printer, watercolour painter and printmaker Margaret Calkin James (1895-1985), best known for the posters she designed for London Transport between 1928 and 1935. She also designed book jackets, textiles, and booklets and programmes. It shows audience members in a theatre seated in the stalls watching a musical theatre performance, with another image below showing passengers comfortably seated in an underground railway carriage. The message it intended to convey was that an evening at the theatre would be more enjoyable and convenient if reached by Underground. Its title 'Q.E.D' indicates that this message has been proved like a mathematical experiment which ends with those letters standing for 'Quod erat demonstrandum', or 'what was to be demonstrated' - meaning that proof has been given.

This was one of many attractive and distinctive posters commissioned for London Transport in the 1920s and 1930s by its publicity officer Frank Pick (1878-1941), who encouraged the use of trains outside peak hours in a bid to increase passenger numbers. He began to commission posters promoting the recreational use of the Underground to reach the countryside around London or attractions within the city, such as the theatre.