Britain/UK is a collection of countries, of which England is one. All English people are British but not all British people are English.
For example I live in Wales, which is part of UK, making me British and Welsh but not English.
Well, I was on my way to this gay Gypsy bar mitzvah for the disabled when I suddenly thought “Gosh, the Third Reich’s a bit rubbish. I think I’ll kill the Fuehrer.”