Sheet size 27 x 45 cm, printed in red and black, blank verso; map of the London underground printed on thin paper and originally folded into an envelope on the pastedown of an official guide book, printed for ‘London’s Underground’ by Odhams Press. The map shows bus, tram and train services operated by the Underground Group, and the specially constructed loop line which ran from Marylebone to the British Empire Exhibition at Wembley stadium. Dodd describes it as a ‘well executed design’. Dodd, Maps of London’s Transport, p. 101