Anyone Know What This Means?

[poliphilo]

A youngish guy in the doctor's waiting room this morning had a jacket with a Union Jack on the back and ENGLAND in big letters and SHUT IT TROUSERS in smaller ones. I've asked Google to explain and it can't.

Comments

[heleninwales.livejournal.com]

I was thinking along the lines of, "All mouth and no trousers," but that doesn't really work in this context.

[poliphilo.livejournal.com]

It sounds like some kind of catchphrase, but if it were you'd expect it to be on the Net.