Great Britain 1863 4d bright red, Plate 4 imprimatur, SG81varGreat Britain 1863 4d bright red, Plate 4 (with hair lines) imprimatur, SG81var. A very fine unused, with original gum, top marginal imperforate imprimatur lettered 'AC', just touched at lower left. This imperforate imprimatur from the first approved printing sheet is very rare as there are only 22 possible examples, several of which are in institutional collections. Stanley Gibbons catalogue value: 3,500.