This was told to me as a true story by my father, who was a navvy, very involved in getting the appalling conditions improved on the sites he worked on
When a site was set up, a large hole was dug somewhere, two oil drums were placed on each side and a plank laid across - then a wooden hut would be lowered over it - that constituted the site toilet
My father said he walked into one of these constructions to find one of his mates down in the pit, up to hi knees in the 'mixture' fishing around with his arm buried in it.
He asked, "What the **** are you doing in there Tommy?"
The man replied, "I came in here to do my business, I took my jacket off and hung it over the end of the plank and it fell in - I'm trying to find it".
"You can't wear your jacket after it's been in that stuff", said my dad.
"I know that Jimmy", came the reply, " but my sandwiches are in the pocket"
Jim Carroll