This is the Inverted Jenny. Printed in May 1918, it feaures a Curtiss JN-4 which is performing a quite unintended aerobatic manoeuvre. Buying one would cost at least half a million pounds today. It owes its extraordinary value to two factors: the obvious printing error and the fact that only one hundred exist. The location of all but two had been known for many years but in May 2016, one of the missing ones turned up. It sold at auction for $1.5m. The final one (known simply as ‘number 66’) is still out there somewhere.
In fact it’s worth keeping an eye out for mistakes on any postage stamp though – even modern ones – just in case you have a rarity on your hands. A recent article catalogued 32 different errors including colours, watermarks, perforations (or the lack thereof), paper, offsets and unprinted areas where a foreign object becomes embedded on the stamp. And in case you thought modern technology would make such mistakes even rarer, you might be surprised to learn that our current Queen’s reign is something of a Golden Age for stamp errors….
A 13p ‘Sweet Briar’ stamp issued to celebrate the Royal National Rose Society in 1976. A small number were printed without the price and all but three were destroyed before they reached the point of sale. One was sold in 2010 for £85,000.