Re Life Presents a Dismal Picture

I heard this in the Royal Army Medical Corps where our sergeant used to sing it. I seem to remember the tune he used was Silver Threads Among the Gold or it might have been the tune of the song that gets bellowed out by all those bloody awful Welsh male voice choirs the title of which I can't remember.

He also used something along the lines of:

Sister Mary's up the spout    (pregnant for you non English)
Little Johnny has just Farted
Turned his arse hole inside out