Great Britain 1840 1d Black Plate 1a, SG2Great Britain 1840 1d Black Plate 1a, SG2. A very fine and fresh unused with original gum four margin example lettered 'JI'. Accompanied by a 1968 Royal Philatelic Society (RPS) Certificate of Authenticity. A very scarce mint example of the world's first postage stamp from the first printing plate. It is very difficult to find mint examples in such fine condition. Stanley Gibbons catalogue value: 18,500. The first printing plate of the 1d black was