The origin of the Keep Calm and Carry On poster

The Keep Calm and Carry On poster is probably the most iconic graphic image of the past decade and this video explains where it came from. The poster was one of three issued by the British government during WWII as morale boosting reminders. And even though over two million copies were printed, the Keep Calm posters were never issued. It would have faded into history had a copy not been found by a small second hand bookshop 50 years later. The owner hung it in the shop, and it proved so popular with customers, she started selling prints. I wonder who gets the royalties?