Great Britain — Penny Black — 1840

The Penny Black was the world's first adhesive postage stamp issued for public postal use in the United Kingdom as part of the Uniform Penny Post reform proposed by Sir Rowland Hill. Printed in black ink by Perkins Bacon on paper watermarked with a Small Crown, the stamp allowed letters weighing up to half an ounce (14 grams) to be delivered at a flat rate of one penny regardless of distance. It was first issued on 1 May 1840 and became valid for postal use on 6 May.

Prior to this reform, British postal rates were complex and normally paid by the recipient upon delivery. To simplify the service, Hill proposed pre-paid adhesive stamps and pre-paid letter sheets. Although an open competition attracted approximately 2,600 entries, none was deemed suitable, leading to the selection of a design endorsed by Hill featuring Queen Victoria's profile. The Penny Black remained in use for less than a year. Because red cancellations were difficult to see on the black design and could be removed to permit fraudulent re-use, the Treasury replaced the issue in February 1841 with the Penny Red, which was cancelled with black ink.

The stamp measures approximately three-quarters of an inch wide by seven-eighths of an inch tall (around 19 by 22 millimetres) and was printed by line engraving on Jacob Perkins's cylinder press using eleven plates. The design features a portrait of twenty-one-year-old Queen Victoria, engraved by Charles Heath and his son Frederick from a sketch by Henry Corbould based on William Wyon's 1834 City Medal. Finely engraved engine turnings form the background, flanked by the inscription "POSTAGE" at the top and "ONE PENNY." at the bottom. The upper corners feature Maltese crosses with radiant solar discs at their centres, while check letters in the lower corners range from "A A" to "T L" to denote the stamp's position within the imperforate sheet of 240 subjects.

It is distinguished from the official VR issue by having crosses rather than the letters 'V' and 'R' at the top, and from the 1841 Penny Red by its colour.