Penny Black print run was 286,700 sheets, containing a total of 68,808,000 stamps. Many were saved, and in used condition they remain readily available to stamp collectors. The only known complete sheets of the Penny Black are owned by the British Postal Museum. In addition to the general issue of the Penny Black, a similar stamp intended for official mail was produced, with the letters "V" and "R" replacing the crosses in the top corners. Because the general public quickly accepted the postage stamps and ridiculed the Mulready stationery produced at the same time, vast supplies of Mulready letter sheets were given
Penny dreadful killed the penny dreadful by the simple process of producing the 'ha'penny dreadfuller'". The quality of the Harmsworth/Amalgamated Press papers began to improve throughout the early 20th century, however. By the time of the First World War, papers such as "Union Jack" dominated the market in the UK. Two popular characters to come out of the penny dreadfuls were Jack Harkaway, introduced in the "Boys of England" in 1871, and Sexton Blake, who began in "the Half-penny Marvel" in 1893. In 1904, the "Union Jack" became "Sexton Blake's own paper", and he appeared in every issue thereafter, up until the