Does anybody remember the phrase "Stop tha' whittlin', Jack"?!

I used a similar phrase when chatting amiably to a relative the other day (a jokey "Stop tha' chunterin'"!), & they recognised it too. Then we both began to wonder WHERE we knew the phrase from & what its origins were, as neither of us could remember where we had heard it. All we could remember was it was very old.

Is it perhaps an old music hall song? a nursery rhyme?

Any ideas?!