POSTAGE DUES: 1961 IMPERF COLOUR PROOF SHEET for 5c dull green (SG D6 design). A complete imperforate plate proof pane of 60 on gummed watermarked paper handstamped in violet at base "CONTROL COLOUR SHEET" and "COLOUR APPROVED" with manuscript endorsements "initials, 28/11/60". Folded at centre, couple soiling marks, generally VF. A wonderful archival piece, probably the sole surviving such example. Rare & exceptional.