Hi Jo, hope you are well, don't know when or how the words got altered, we used to sing it as kids this is the original as Octavius says written by Bert Hansel, take care and enjoy.
I was outside a lunatic asylum one day, busy picking up stones
When along came a lunatic and said to me, "Good morning Mr. Jones,
Oh, how much a week do you get for doing that", "Thirty bob I cried"
"What, thirty bob a week, with a wife and kids to keep?
Come inside you silly ****** come inside"
"Come inside you silly ****** come inside, you ought to have a bit more sense.
Working for your living, take my tip, act a little screwy and become a lunatic.
Oh you get your meals most regular and a brand new suit besides.
What's thirty bob a week with a wife and kids to keep.
Come inside you silly ****** come inside."