In a June, 2005, episode of 'New Tricks', Brian Lane of UCOS referred to his boss Sandra Pullman as "She Who Must Be Obeyed".
The phrase comes from the novel "She" by H. Rider Haggard, the full "honorific"/name for the title character. And that could be where Brian knows it from. I could see "Memory" Lane having read it as an impressionable youth; remembering that title and recognizing it as the perfect definition of his "guv'nor".
But of course, this is Toobworld.....
I'd like to think that Brian picked up on the derogatory aspects of the name from another Toobworld character, one of the true classics - Horace Rumpole. Over the years, 'Rumpole Of The Bailey' used "She Who Must Be Obeyed" when talking about his wife Hilda. It could be that at some point over the years when Rumpole's career as a barrister overlapped the police service of Brian Lane, the two men met and perhaps even shared a glass of "Chateau Thames Embankment"... despite being on opposite sides of a case (one that probably concerned the Timson family). Brian may have shown - with his incredible memory - that he had a similar talent to Rumpole's in quoting Wordsworth and others.
And if so, Rumpole's ruminations would invariably lead him to mention Hilda... and as always, as "She Who Must Be Obeyed". Brian, probably incapable of ever forgetting anything he heard, would have stored away the sobriquet for future use... when Sandra Pullman fit the bill.