In the US they are called Victory keys. Here is a link to the particular patent, (if it still works).
http://patimg1.uspto.gov/.piw?docid=US0 … PN/2301531
That was the result of a patent number search at this site:
http://www.uspto.gov/patft/index.html
Patents of that age are not available as text but they do have scanned images so click on the Images box at the top of the page. As you can see, the date was 1942 and the approval had unprecedented speed from filing to grant. Being involved in the war effort, things that had the potential to save brass were routinely adopted. The main purpose here of course was to make key blanks that didn’t require as much brass in the making process. It was much more conserving to have two smaller strips of brass to punch parts out of than a single larger strip.
During this same era there were many brass drives in the US and countless locks and keys were given up to the smelter for their brass content.
Earlier than WWII, there was a lock manufacturer in the US named Vassar who placed a large letter V on the bow of their keys and those are sometimes mistaken for victory keys by newer collectors.
BBE.
