Starring David Tennant (Doctor Who) and Janet Montgomery, BBC Four’s Spies Of Warsaw is a new spy story set in Poland, Paris, London and Berlin in the years leading up to the Second World War. French and German intelligence operatives are locked in a life-and-death struggle on the espionage battlefield.

Episode 1 airs at 9pm on Wednesday 9 January on BBC Four.

> Buy Spies of Warsaw on DVD on Amazon.

What attracted you to Spies of Warsaw?

“Initially the attraction came because I know Richard Fell, the executive producer, and Coky Giedroyc, the director: Coky from [the BBC musical comedy drama] Blackpool, and Richard from The Quatermass Experiment, which was an extraordinary (and rather terrifying) live TV drama that the BBC filmed a few years ago. So, getting an approach from both of them – you kind of think, OK, I’d better take this quite seriously. I’d better have a good look at this. Also, the main character seemed like quite an unusual role for me. So that was an exciting prospect, too.”

Were you a fan of Alan Furst, the US novelist who wrote the original book?

“I have to be honest, I hadn’t come across any of his stuff. I don’t know if people in Britain are as aware of him as they are in the States, where he’s a hugely popular author. So when this came through, I went into my local bookshop and found a shelf that was full of his novels. They are mostly wartime, espionage novels – and they all hang the fiction off actual events. Sometimes even actual people. Winston Churchill’s secretary Duff Cooper is in this one, for example.”

How would you describe Spies, for the benefit of people who haven’t come across the novel?

“It’s based between the First and the Second World Wars and set principally in Warsaw – although all over Europe at different times. And it’s the story of Jean-Francois Mercier, a French cultural attaché in Warsaw, who also has this clandestine professional life where he’s spying for the French on the Nazis – and anyone else who comes into view, really.”

And how would you describe Mercier? What’s he like?

“His background is that he’s a ‘chevalier’, so he’s minor aristocracy. And he’s a military man who has been decorated and has had great successes in Poland and in France. I would say he is motivated absolutely by his duty, but also by his personal morality. And I think that’s how we start to see him coming up against his own superiors, because he believes they are not treating Hitler with the respect he deserves – that actually he’s a bigger threat than anyone is willing to accept.”

So at this point, war isn’t a given – people are still hoping that everything will end peacefully?

“Exactly. It’s stripping back the idea that World War II was an immovable moment in time. I mean, Mercier does see war as absolutely inevitable. But he’s surrounded by people who don’t. Particularly within French intelligence – which I think is quite an accurate portrayal of what was going on at the time.”

Warsaw suffered terribly in the War. How did it feel to be filming in the city where it all took place?

“There’s so much resonance to want went on, because it was so graphic and ghastly. I’m not a historian, and there would be other people who are better equipped to talk about this. But as I understand it, Warsaw was utterly destroyed in the Second World War. Hitler at one point allegedly said, “Turn it into a lake…” So they did.”

But you were filming in the Old Town of Warsaw – what’s that?

“Well, it’s an extraordinary place. When the War ended, the people of Warsaw basically rebuilt the Old Town, brick by brick, exactly as it was. And it has been preserved ever since. It’s not a museum. There are restaurants open. People live in the apartments. People work here. But from a filming point of view it’s fantastic, because you have all these streets that are exactly as they were 70 or 80 years ago.”

Has Poland rubbed off on you since you’ve been out here?

“I’ve been enjoying the Borscht and the Pierogi! Our caterers here all supply it with great aplomb. Pierogi is like a kind of Polish ravioli. Sort of dumpling-ish. But I think Borscht is probably my favourite. It’s beetroot soup. It’s delicious.”

Have you been encountering any Doctor Who fans in Poland?

“A few! I didn’t realise that Doctor Who plays in Poland, but it obviously does. I’ve had a few coming up to me, wanting to say hello, maybe wanting a photograph or a signature. It doesn’t happen quite on the ubiquitous scale that it happens at home – but then I don’t think I’ve been to a country yet where I haven’t been met by someone who’s a Doctor Who fan. Except maybe Uganda.”

Would you say that spy thrillers are making a comeback?

“I don’t know if they’re making a comeback, exactly. We had Tinker Tailor Soldier Spy recently. And James Bond has always been there. But I’ve never come across anything quite like Spies of Warsaw. Because although this is a spy story, it’s also a love story. And it’s also a historical piece. It’s quite unusual and hard to categorise. But at the end of the day it’s a gripping yarn as well. And however much we like to dress it up, that’s ultimately the most important thing.”

> Buy Spies of Warsaw on DVD on Amazon.

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