Great Britain is an island including England, Wales and Scotland.
The United Kingdom is England, Wales and Scotland plus Northern Ireland.
I live in Wales, so am Welsh and British, but not English.
Meanwhile, Project Gutenberg has recently added a zombie story by Lester del Rey:
Dead Ringer. I've converted it for the MR library:
LRF:
https://www.mobileread.com/forums/showthread.php?t=59389
IMP:
https://www.mobileread.com/forums/showthread.php?t=59390
LIT:
https://www.mobileread.com/forums/showthread.php?t=59391
PRC:
https://www.mobileread.com/forums/showthread.php?t=59392