Sudan 1902 1m brown and pink Official error, SGO3c/dSudan 1902 1m brown and pink Official, Type O1 'O. S. G. S.' overprint, vertical pair, 'ERROR OVERPRINT INVERTED', from position 19 13 of the setting, position 19 additionally with printing variety Oval O, SGO3c d. A brilliant quality mint vertical pair with original gum. A great rarity of the British Commonwealth, with only six examples possible of the oval 'O', of which one is in the Royal Philatelic Collection and another was used. The Camel