We of the Yard seldom pay heed to theatrical notions of that kind.

Here is the article.

I don't mind letting you see it, but kindly remember that its existence must not be made known.

I must have your promise not to mention it to a living creature." Furneaux chuckled derisively.
"That is precisely the sort of thing anybody would say who attached no importance to the exhibit," he piped.
Winter so nearly lost his temper that he repressed the retort on his lips.

He contented himself, however, with producing a small white object from his waistcoat pocket, and handed it to Theydon.