In Sherlock: A Scandal in Belgravia, the Americans force Sherlock to open Irene Adler's safe by threatening Holmes and Adler at gunpoint. The safe turns out to be booby trapped. But just before he opens it Sherlock mutters something to warn them.

What does Sherlock say and why does it cause Adler and Watson to react the way they do?

3 Answers 3


Just before he opens the safe, Sherlock looks at Irene (probably because he suspects there might be some kind of booby trap). She looks sharply down and to the right. It's obvious given what happens next that this look is code for "Duck!"

So he knows to duck, and she knows to duck, but someone has to warn John somehow. You can see from John's reaction and expression immediately after Sherlock yells, "Vatican cameos!" that he's reacting specifically to that phrase, not because he had any previous intent to duck.

Googling reveals that there seems to be some sort of myth going round that this is a phrase used by military personnel to indicate that there was an armed (non-military) person who had entered the base. I say myth because, despite it being repeated an awful lot on Tumblr, Yahoo! Answers and Urban Dictionary, I've yet to find a single corroborating source for it. It's also nicely debunked here.

The single place we do know of the phrase being used (prior to Sherlock) is in the original Sherlock Holmes stories.

“I was exceedingly preoccupied by that little affair of the Vatican cameos, and in my anxiety to oblige the Pope I lost touch with several interesting English cases. —Sherlock Holmes, The Hound of the Baskervilles

So, it's a nice little nod to the original stories, as we know the writers of Sherlock are keen on doing.

But what does it mean in-universe?

This is definitely a codeword very precisely targetted at John. Most likely, it's a reference to a case that Sherlock and John worked on together. The fact that it isn't explained in any more detail than "saying 'Vatican cameos' makes John duck" isn't particularly unusual for the series.

For example:

  • Sherlock attacking a corpse with a riding crop in the very first episode.
  • Sherlock harpooning a pig and arriving home (via the Tube!) drenched in blood at the start of The Hounds of Baskerville.

And even an example of a past case being a codeword:

  • In the unaired pilot, Sherlock says, "Angelo, headless nun" to refer to a past case. Angelo simply asks, "Same again?" and when Sherlock confirms, Angelo throws him out of the restaurant as if he were drunk.

Finally, this is brought up again in The Sign of Three, with slightly more explanation as to its meaning (if not its origin).

JOHN: Oi! Sherlock! Any chance of an end date for this speech? Got to cut the cake?

SHERLOCK: Oh, listen to him. Can’t stand it when I get a chance to speak for once vatican cameos.

[He just adds the last two words, casually appending them to the sentence. Their eyes meet for a deadly serious moment. ]

MARY (To John): What was that?

JOHN: Battle stations. Somebody’s going to die.

[On Sherlock, scanning the room. So many Texts, so many potential Mayfly men ...]

BBC Script - The Sign of Three

It's not clear whether it literally means "battle stations" or whether that's John's translation for this context (much as his translation for the previous context was "the safe is trapped, get down"). However, it's slightly more information than in Scandal.

  • 4
    +1 for the reference to The Sign of Three. Regardless of its source, it was an understood code phrase between Watson and Holmes. Jun 2, 2014 at 23:17
  • I've taken the liberty of linking to the actual show script
    – Valorum
    Dec 10, 2023 at 15:55

Vatican cameos!

It's pretty hard to find a definitive answer, but it looks like it is code for "Duck!".

And it's aimed only at Watson as he's the only one to react at the phrase.

Conan Doyle makes a reference about in "The Hound of the Baskervilles". (source)

I was exceedingly preoccupied by that little affair of the Vatican cameos, and in my anxiety to oblige the Pope I lost touch with several interesting English cases.

But Conan Doyle never wrote a story about it.

  • 1
    Well, that's what I mean by "it looks like". There's no explication given in the episode. And it isn't a reference to a previous one. So there's no definitive answer for the use of "Vatican cameos" Jan 22, 2012 at 20:31
  • 4
    For what it's worth, I've asked the writers on Twitter. We'll see if they answer. Jan 22, 2012 at 20:36
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    It's possible that the untold case of the Vatican Cameos, as referred to in The Hound of the Baskervilles, somehow involved ducking to avoid gunfire, an event that Holmes was hoping was memorable enough to illicit the response in Watson that it did. Jan 27, 2012 at 21:47
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    From what I can find, "Vatican Cameos" was a code used by the English during WWII to alert agents that the person they were dealing with was an armed enemy/double agent. This fits the situation as the safe was booby-trapped.
    – phantom42
    Jul 24, 2012 at 14:48
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    See also: bbc-sherlock.wikia.com/wiki/Vatican_Cameos
    – Hugo
    Aug 21, 2012 at 12:42

Vatican Cameos is a codeword used between Sherlock Holmes and Dr. John Watson. It originated in WW2 when a non-military figure would enter a military-base armed. Vatican Cameos would be shouted and everyone would duck.

Having been in the military, Dr. Watson understands Sherlock's meaning and does indeed duck.

  • 2
    This might well be true, but I'd love to see a proper explanation of how and why the code was invented.
    – matt_black
    Mar 1, 2014 at 12:08
  • 10
    I've seen this answer a lot on Yahoo! Answers and on Tumblr. It's even the top explanation on Urban Dictionary. However, I've yet to see a corroborating source for it. Any chance you could add one? Jun 2, 2014 at 18:41

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