Great Britain 1856 1s pale green, Plate 1, on azure paper, SG73aGreat Britain 1856 1s pale green, plate 1, on azure paper, SG73a. A superb used right hand wing margin example, beautifully cancelled by a crisp "Rideout" number 1 experimental machine cancel. Excellent bluing of the paper. An exceptional example in all respects. An extremely rare stamp and only known to exist in used condition, with this example being one of the finest known. This value was introduced to replace the Embossed issue. This was an