Millions of Penny Reds were printed between 1841 and 1879. There were flaws in one of the printing plates (No. 77) which meant that the perforations of the stamps were lined up incorrectly. In the example above, you will see “POSTAGE” being cut off due to the incorrect alignment of the perforations. All the test sheets were destroyed, but one sheet was released into circulation by mistake. Stamps from this plate are very valuable and sought after. In 2012, Stanley Gibbons regarded one of these Penny Reds as the most valuable single stamp the company had ever had for sale in their 156 year history. It was given a value of about £550.000. Only about 4 mint and 5 used examples of the stamp have been reported, but they have not been seen for a very long time.