Great Britain 1935 2½d Prussian Blue error, SG456aGreat Britain 1935 2d Prussian Blue, SG456a Error of Colour A superb unused original gum example of the famous 1935 2d Prussian blue, issued for the Silver Jubilee of King George V. This is the celebrated "error of colour", where the stamp was mistakenly printed in the Prussian blue shade intended for the 2d definitive instead of the intended ultramarine. This example displays exceptional freshness, full perforations, and strong colour. A top tier