Bradbury Wilkinson, one of Britain’s legendary security printers became part of the De la Rue group in 1986 and in 1990 all printing at Bradbury’s plants ceased. These Promotional sheets were produced after the merger with de la Rue. This particular group was overprinted on the back to say they were given to attendees at the International Banknote Society Annual Congress in 1992. Now 30 years old, the front features a portrait of Sir Isaac Newton with an apple tree as a background alluding to how Newton was inspired to formulate his law of gravitation. Measuring 215 mm x 135 mm (about the size of a white Fiver) they are in Uncirculated.