There's a bike frame available on my local Craigslist manufactured by Hercules bicycles in England. The model is the Royal Prince. This one was made in Birmingham. I believe later models were made in Nottingham after Hercules was acquired by Raleigh.

This is a "diamond" frame with fork, headset and handle wheels. I have not seen the frame in person but looks in decent shape from the pictures.

Anybody know anything about these bikes? Really cool headbadge. I'm thinking about a fixie conversion but could be more hassle than it's worth. The bike is circa 1940 to 1965.