The version I learnt in the early 1950s was slightly different:
Outside a lunatic asylum one day, as I was picking stones,
A lunatic came up to me and said, 'Hello, Mr Jones!
How much do you get for doing that?'
'Fifteen bob', I sighed.
He looked at me with a twinkle in his eye,
And this is what he cried:
'Come inside, you silly bugger, come inside!
I thought you had more sense.
Working for a living? Be like me,
Act a little funny, be a lunatic!
You get your meals regular, a brand-new suit besides.
Thirty bob a week, no kids to keep, come inside, you silly bugger, come inside!'