Britain had been Catholic and then became Protestant.
I refer my honorable friend to the 1981 movie "Stripes" and the role of Sergeant Hulka played by American character actor Warren Oates, specifically to one of the all time greatest lines delivered in American film history.
"Lighten up, Francis."
Greatest Britain? There's also a move to rename Canada as Northest America.
BTW, go tell an actual Englishman that England used to be Catholic. Of course that same hypothetical Englishman would react the same way if you said England isn't Catholic now. It's a weird POV they have over there.
You wrote:
“Britain had been Catholic and then became Protestant.”
Incorrect. Great Britain only came about as a nation when England, Wales and Scotland - all Protestant countries - became one united state under one Protestant monarchy in the early 17th century.
Like I said, I think you need to read more history.