Great Britain 1902 10s Ultramarine (I.R. Official). SG O26Great Britain 1902 10s Ultramarine (I. R. Official) 29. 4. 02, SG O26. A very fine and fresh original gum example of this rare departmental issue and one of the key rarities of GB philately. Perforations at top are slightly trimmed and a couple of light gum wrinkles. Nevertheless, a magnificent GB rarity with superb colour. These stamps were used by revenue officials in the provinces, mail to and from Head Office passing without a stamp. The London