Thought there might be some Mudcatters who would know about this and maybe shed some light on it. This came in the Kovell's (Antiques & Collectibles)email newsletter in answer to someone's query:

Teapots similar to yours were made during World War II, but not for the soldiers, who were much too busy for tea. They were made to raise money for the war effort. The teapots we have seen are black, like yours, and are decorated with flowers. A few were made in a smaller size. The words "For England and Democracy" are usually printed around the lid. Teapots with the words "Escorted to U.S.A. by Royal Navy" were also made. From 1939 until the end of the war in 1945, ships crossing the Atlantic were protected by Allied escort ships from the United States, Canada and England. The mark on the bottom of the teapot is the Staffordshire knot, indicating the pottery was made by one of the Staffordshire potteries. There is probably more to this story. Can anyone tell us more?

You can see the mark on This Page.

This ought to be fun!