Postage stamp prepaying. From when the first postage stamps were used, postmarks were applied to prevent the stamps being used again. The first stamp, the "Penny black", became available for purchase 1 May 1840, to be valid as of 6 May 1840. Two days later, 8 May 1840, the Two penny blue was introduced. The Penny black was sufficient for a letter less than half an ounce to be sent anywhere within the UK. Both stamps included an engraving of the young Queen Victoria, without perforations, as the first stamps were separated from their sheets by cutting them with scissors. The first
Revenue stamp have sometimes combined the functions of postage and revenue stamps. In the former British Empire, such stamps were often inscribed ""Postage and Revenue"" to reflect their dual function. Other countries have simply allowed revenue stamps to be used for postage or vice versa. A revenue stamp authorized subsequently for postal use is known as a postal fiscal. Bhutan, for instance, authorized the use of revenue stamps for postal purposes from 1955 until the first proper postage stamps of the country were issued in 1962. In the Stanley Gibbons catalog, this type of stamp has an F prefix. While revenue stamps