I’ve realised that I have the same problem with John le Carré thrillers as I did with The Americans: I don’t understand where reality leaves off and fiction begins. You should have seen my face when it was confirmed for me that there really were – ARE!?!!? – Russian sleeper agents strewn across the US, ready to overthrow the evil of capitalism the moment the fax came through. I mean, it’s insane. But, apparently, true.

I’ve always shelved spies in much the same category as King Arthur. Some tiny grain of truth somewhere along the way providing a storytelling opportunity too good to miss and here we are: a mythology so irresistible that we are happy to cleave to it as fact. I no more think of James Bond as a glamourised, ironised take on reality than I think of Spiderman as a Hollywood version of real arachni-heroes. He’s just another offshoot of the tale we tell. As for Philby and Co – well. I vaguely presumed that they were people who had forgotten what lies they told at their entrance interviews and that the situation just kind of ran away from them after that.

Espionage. Counterespionage. Where would you find the energy, the motivation? People don’t really get that worked up about their countries, do they? Ah, but here is where even the thickest carapace of ignorance must begin to crack and let a little light shine in. Because, of course, as even the most unwilling of us have learned over the last few elections and referendums, they do.

And the most potent example of it is at the heart of the latest Le Carré adaptation. The Little Drummer Girl, whose six-part run began on Sunday night (brought to us by the same people who gave us The Night Manager two years ago, though its lavish, stylish direction comes courtesy of Korean auteur Park Chan-wook) begins with a bomb exploding in the house of an Israeli attache in West Germany, missing him by chance but killing his eight-year-old son. The bomb was planted by a young woman working as part of a network of cells operated by a brilliant and elusive Palestinian named Khalil. It provides the cue for Martin Kurtz (played by the estimable Michael Shannon), the head of a team of Israeli spies working clandestinely – like, even for spies – to step up his mission to find Khalil and stop him. I suspect not by asking him politely.

In order to fight fire with fire, Kurtz deems it necessary to recruit a young woman for their side too. I was going to say “slightly implausibly” but again – see The Americans above – I really don’t know. Is it? Should we be marvelling at the accuracy of the rendering of history or at the brio with which nonsense is being made credible and compelling?

Whichever way we choose, we can all be grateful for it bringing Charlie into the game. She is played by Florence Pugh with such authentic pugnacity, compressed energy and intelligence that were she not surrounded by such stalwarts as Shannon and – soon to come – Alexander Skarsgård she would be in danger of making everyone else look like a bloodless cipher.

Charlie is an actor on a working holiday in Greece with her castmates, paid for by their new anonymous patron. There they are approached by and befriend – you know what actors are like, basically fools – a strange, scarred man called Joseph (Skarsgård in a part that puts to perfect use his strangely ethereal charisma and persistent undertow of melancholy). She alone is suspicious, noticing among other things that he hums a tune unique to the show they did in London before they left.

Eventually, and via that rarest of phenomena, a plentiful array of scenes during which they test each other and forge a convincing, idiosyncratic relationship instead of one that simply relies on her being a Hot Young Actor and him looking like Alexander Skarsgård, she agrees to a sort-of date. At the end of it she discovers that her acting ability, ferocious memory and potentially sympathetic politics have made her ideal recruiting material for Kurtz, rather than girlfriend material for Joseph. While he has been seducing her, the rest of the team have been surveilling Khalil’s younger brother Salim – and from next week, the hunt is on.

It’s all brilliantly, beautifully done and the dialogue sounds as good as everything else looks. By the end of the hour you’re more firmly recruited than Charlie is. Do I know what is real and what is not? Do I know where to position myself at the border between fact and fiction? I do not. Let Le Carré and his team determine my truth. I’m along for the six-week ride.