This is the funniest card I've ever seen!

It really is!

I showed it to the shop assistant and two guys collecting for the Salvation Army. None of them got the joke.

I wonder if Peter and/or Robert will?

They certainly didn't have jokes this good in 3P in 1966! I don't know whether a Presbyterian or a Catholic are more likely to get it.

Ah well, I guess the comments left will tell the story.