The London Transport Museum in fact has ten posters by Margaret Calkin James in their collection here, all of them designed between 1928 and 1935 and this one in 1929. It’s also in the V & A, which says here: ‘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.’ Margaret Calkin James designed three fabrics that we have used as endpapers, for The New House, The Runaway and Gardener’s Nightcap; we sell the fabric for the latter in the shop, and cushions made out of it; and also have the Rainbow Workshops poster hanging at the back of the office (it was used on the front of the book about her by Betty Miles). This poster is unusual in being signed.