THE American 1918 inverted "Jenny" is one of the most famous stamps in the world. It features a Curtiss JN-4 Jenny in flight, mistakenly printed upside down. Only one sheet of 100 of the 24 cent stamps were printed incorrectly and the inverted "Jenny" has soared in popularity and value. The profitable mistake was first discovered by stockbroker's clerk William Robey in May 1918 as he went to buy examples of the new airmail stamp. When he noticed the error - on only one sheet of 100 stamps at the post office in Washington DC - he bought the whole sheet. The value of the rare creations soon became well known and after a flurry of offers, Mr Robey sold the sheet to a syndicate for $15,000 (10,470). It was sold on then broken up but the examples carried on gaining value and in 2007 two were sold at auction for $825,000 (575,000) and $850,000 (593,000). Today auctioneers Warwick & Warwick said this example is expected to fetch around 150,000 when it goes under the hammer on Wednesday. Stamp valuer Ian Hunter said the stamp had come to them from a British collector. The stamp will go under the hammer in a sale at the Court House, Warwick, on Wednesday. - Daily Telegraph