I always thought of the song "Father Christmas", by Greg Lake to be sort of an "anti-Christmas" song. It seems to me that it debunked the "fairy tale" aspect of Christmas. And yet, here Lake is, with Ian Anderson, performing it in a freaking cathedral. What is up with that?
Christians are notoriously humourless morons.
You ask most British Christians what the greatest hymn ever written was and they will answer reverently "Jerusalem" they will even quote the lines of the first verse with great deference.
The Lyrics of Jerusalem (The Poem "And did those feet in ancient time" ) were first written as an anti-Church of England satire by William Blake, the notorious mystic and metaphysical poet and thorn in the side of organized religion.