Mark Finnell

No Cold War expert, but I've seen some James Bond movies, and did they just freak out a little bit when they realised that somebody clearly had a listening device on the US ambassador in the Soviet Union at the height of the Cold War?

Like, did they just freak out a little bit?

Yes, it is one thing to know you're being spied on.

It's another to not know how you're being spied on.

The Americans searched the ambassador's residence inside and out.

In fact, they looked everywhere for this thing.

So what exactly are they looking for?

If you're looking for a recording device back in the late 40s, early 50s, what sort of things would you be doing to locate a bug?

So it actually takes them quite a while, but eventually somebody notices something on the wall, right?

And when they did notice that, did they just start hacking at it?

Because in my mind, that's what happens.

Yeah, they cracked it open.

Unlike traditional bugs, the thing, as the Americans seriously called it, it contained no wires, no battery, no active electronics.

Instead, it was a passive cavity resonator, meaning that it remained dormant until it was activated by an external radio beam, and only then would it transmit audio.

Right, so that goes some way to explaining why they couldn't hear it all the time, because it basically, without having a power source of its own, it required somebody outside to effectively trigger it.

Exactly, yeah.

So they must have gone back and looked at the seal and went, hold on, who gave us this thing?

No.

Moral of the story, never trust a scout bearing gifts.

Okay, so this device went undetected for years, right?