A frame with border in the colours of the Union Flag. I imagine it would look good with a picture of the Houses of Parliament or Queen Elizabeth II in the middle of it.
This is a completely free image UK Union Flag frame that you can download, post, and use for any purpose.
Image License: CC0 No Rights Reserved
You can copy, modify, distribute and perform the work, even for commercial purposes, all without asking permission, and at no cost. This image is completely free.