The UK has about half the land area of California, but about 1.5 times the population.
The UK economy is slightly larger than California.
Most folks don't realize how small England is.
My guess is the Brits were in a tough situation. It wouldn't take much more of an influx to obliterate England. Look at London.
This is WW3, and the Germans are winning. Is it really surprising that tradition-centered Brits voted out?