The British threepence (3d) coin, usually simply known as a threepence or threepenny bit, was a unit of currency equalling one eightieth of a pound sterling, or three pence sterling. Threepence coins had been issued for a long time as "Maundy" money (non circulating legal tender, distributed in very small amounts by the King or Queen in person), then for regular circulation in Britain since 1845 (earlier circulation pieces were for colonial use only).
By the end of King George V’s reign the threepence had become unpopular in England because of its small size. Although it was still popular in Scotland, the government of the day decided to introduce a more substantial coin which would have a more convenient weight/value ratio than the silver coinage. King Edward VIII expressed his wishes that his coinage would be modern, with new and exciting designs; he hinted at his admiration of the Art Deco style but he also fully understood the conservative nature of the Royal Mint and its traditions. The Royal Mint set about designing the new coins, testing the minting process and, in particular, checking for flaws in the metal flow. A nickel-brass (79% copper, 20% zinc, 1% nickel) twelve-sided threepence coin was introduced, in parallel with the existing silver version which continued to be issued until 1945.
Owing to the early abdication of King Edward VIII, none of the patterns made during his short reign was ever released into circulation. These include both silver and brass versions. Maundy coinage for King Edward VIII was not minted either.