John le Carres George Smiley would have spotted the tail immediately.
Let me back up a bit.
Guests are finishing dinner, were here for the after-party.

Martin Scorsese and Leonardo DiCaprio, Scarlett Johansson with Colin Jost and Lily-Rose Depp at the Air Mail Party.Getty/Baz Bamigboye
Watch on Deadline
The place sure looks swell.
Theres a full length wall of mirrors stencilled with Air Mail and Warner Bros. logos.
Ash-trays and match boxes are cannily branded.

David Zaslav chatting to a guest at the Air Mail-Warner Bros Party.Photo Bamigboye/Deadline
Lamps are emblazoned with images from classic Warner Bros movies.
There are searchlights lighting up the sky.
Video of gangster classics and Batman films are beamed onto the luminescent pool.
These are Carter touches.
Hes a master host, knows how to pull off this classy stuff in his sleep.
Boy George makes an appearance.
Hes performing gigs in the area in coming days.
Zaslav appears and I wonder over, introduce myself and compliment him on the swanky style.
He asks if Im having a good time.
A short while afterwards a bulky guy stops me.
People come and go.
Shes chatting to Jim Wilson, the Brit producer of Jonathan Glazers acclaimed filmZone of Interest.
Lily-Rose Depp arrives with Troye Sivan, a co-star onThe Idol.
I see Sting and Trudie Styler.
The film producer Celine Rattray is there.
Daphne Guinness rocks up sheathed in silver sequins and shes somehow managing to walk wearing bejewelled platformed boots.
I say hello to CAAs Bryan Lourd, Robert DeNiro, and countless others.
The space crackles, theres excitement, theres buzz.
Not the place for anything hardball.
Then the bulky, beefy guy approaches.
Hes Zaslavs head of security, not Leos.
Im confused because Zaslav has said no such thing.
Zaslav walked around me and then went away.
The head of security explained that was Zaslav telling me that he didnt want his photo taken.
Okay, thats a body-language thing that hadnt translated.
I guess because I wasnt in combat mode.
I go off and chat with other people who dont run away.
I spent a year and a half researching.
They gave me everything l nothing was held back, Iwserks assured.
My phones tucked away in my man bag.
Im clearly not going to take a snap of him.
Head of security pounced on me.
Whered he come from?
I smile, put my hands up and say: Look, no pictures.
Im gong to ask a very polite question.
Im persuaded not to even try.
I dont want to create a scene.
Im also keen not to be grabbed or escorted outta the party.
I project calm, nice vibes to get head of security off my back.
I go walkabout and chat to other people.
About 20 minutes later I notice another gentleman who is obviously a security dude.
On my right, theres another one.
Im a massive fan of crime and spy thrillers.
I should have been more observant, obviously.
Paranoia brought on by sipping too much cranberry and orange juice.
My instinct was to leave, but I thought better of it and stayed a while longer.
The music was fun and there was Zaslav on the dance floor for a three second dance move.
Hes light on his feet.
I cant dance for toffee but Im a fan of choreographers so Im impressed.
I do not go near him.
Im wearing a nice tux, a Jermyn Street dress shirt and I do not want them ripped.
They didnt call me The Tank for nothing.
Still had a good time though.
The man understands that people want to be fed decent nibbles and to feel comforted and relaxed.
Even when theyre being tailed under the orders of David Zavlavs head of security.