My personal vision of a redesigned Union Jack, with a shade of blue more closely matching that of (most versions of) the Saint Andrew's Cross, along with a green portion at the bottom. The general idea being red for England, blue for Scotland and green for Wales, which is presently unrepresented in the current flag.
Additionally, the shades of red and green are designed to match those of the old 19th century British Republican tricolour, as per my personal preference for Britain becoming a Republic (see: https://commons.wikimedia.org/wiki/File:Flag_of_the_British_Republic.svg )

I feel the shade of blue is a better fit with the red and green compared to navy/dark blue, and if anyone asks, the omission of the Saint Patrick's Cross is deliberate.
Own work
Charlie Halson