Letter sheet, A30, addressed to "Her Majesty's Board of Commissioners for Stamp Duties, Somerset House, London", showing red London "PD/MY 5/1840" datestamp and black "T.P/KING WILLIAM ST.", manuscript "1", the interior prepared as an essay for the printed advertisers, mocked-up using company advertisements pasted inside and inscribed in ink at lower-right "The above are slips promiscuously taken to show an outline of what the system will in all probability soon become if generally adopted. The print must be supposed imprinted on the cover itself."; light creasing. An extraordinary item of great philatelic importance. B.P.A. Certificate (1989). Photo