The Penny Black was the first adhesive stamp for general use - and the first stamp to be forged. It was launched on May 6 1840; the earliest surviving used example was sold 151 years later for £1,350,000.

Forgers worked out that forging the Penny and Twopenny Black for postage could never bring in more than one and two pennies respectively. Rare stamps provided a better return on capital. They figured out that stamps were indeed worth more to collectors than to people merely putting them on letters.

The golden age of philately fraud ran from the 1860s to the 1930s. It began with the "Boston Gang", which was printing its own bogus stamps for Guatemala and Paraguay years before those countries were issuing any official versions of their own. Less competent rivals produced a five-cent model labelled both "USA" and "Labrador". Another purported to originate from the Indo-Chinese kingdom of Sedang, which did not actually exist. This stamp had a face value of "2"; two of what, it did not specify.

As well as the genuine forgery, there was also the genuine forged forgery. The ultimate accolade for an invented design was for it to be in turn copied unwittingly by another forger. The first forger has, naturally, no legal redress against this breach of his copyright. Some collectors actually collect bent stamps. At least, the stamps are supposed to be bent.