Great Britain 1968 1s6d British Bridges error, SG765aGreat Britain 1968 1s6d British Bridges error, SG765a. Superb Post Office fresh unmounted mint, with full original gum, example with gold (Queen's head) omitted, offered with a normal example for comparison. A rather unusual error, with the missing gold colour resulting in the Queen's head appearing in sky blue, which is the underlay colour, rather than gold. A scarce and reasonably priced QEII stamp error. Pierron records only 120 known mint