In your new book Every Spy a Traitor you move away from a World War II/Post War setting and focus purely on a ‘Cold War’ with the Soviet Union in the 1930s. What was it that attracted you to the period?

I liked the idea of a series that covered a longer time span, because in the Second World War, particularly in Europe you’re dealing with a 5/6 year timescale. I fancied the idea of something that was a bigger sweep of history. So the series starts in the mid-thirties with Stalin’s Great Purge and also the rise of Nazism.

Then the second book is set in 1940. The third book will be set in 1945 and that will be the end of the Second World War and the very beginnings of the Cold War. There was a period at the end of 1945 really up until the Berlin Air Lift, when it wasn’t quite a cold war. It’s those early tensions that I want to get into. Then what is planned as the last book that’s going to finish in 1956, when it’s a fully complete Cold War. 1956 was when Communism lost a lot of its support, after Khrushchev made his speech denouncing Stalin and then of course there’s the uprising in Hungary.

I liked the idea of taking the series over a twenty year period and seeing how it felt. At the heart of it is the main British traitor, Agent Archie, I’ve got to have him at the forefront of the stories, but I’ve also got to keep his identity secret through four books and that’s a hell of a challenge.

The Secret Intelligent Service was penetrated by Soviet moles in the 1930s and it also failed to recognise the full threat of Nazi Germany, why do you think it was so easily deceived?

Well I think they were deceived as far as the Nazi threat was concerned because they never rated it. They were obsessed with the idea of a Russian threat, but their perception of a Russian threat was Communists in this country; so people in trade unions, people standing on street corners selling the ‘Daily Worker’. I don’t think they ever had a grasp of the fact that the real infiltrators, the real traitors were their own type.

I think we forget how much of a class system it was. You look at the British traitors Philby, Maclean, Burgess and Blunt. They were all the same class, all from the same background as the people that would have been involved in running the Foreign Office and running the Secret Intelligence Service. So they never clocked that was where the threat was coming from, but instead they were very good at making long-lists of who got the ‘Daily Worker’ and who was going to what meeting.

In truth some trade unionist shop steward in Bolton, who joined the Communist Party was no more of a threat to this country than the next person, but I think that’s how they saw it. They were obsessed with the Communist threat.

If you look at what was going on in Berlin, the British Passport Office which was the front for MI6 was relegated to an office in Tiergartenstraße. The head of it Frank Foley didn’t even have diplomatic status, they regarded espionage in a slightly disdainful way. It wasn’t quite the done thing.

So I think it was a mixture of ineptitude and bias and also class warfare if you like, that might be the wrong way of putting it, but it was certainly class attitudes.

There is a nod and a wink to Kim Philby in Every Spy a Traitor, with your character ‘Agent Archie’, but you have featured real historical people in other novels like Klaus Barbie, The Butcher of Lyon and Admiral Canaris the Head of the Abwehr. How do you decide whether to use a real person or a fictional character and how difficult do you find it to get the tone of a real person right?

I’ve thought about that a lot. There are some people I won’t use, I don’t think I would use Churchill as a character. He is too big and too well known. I do have him as someone in the wings, so some other character will say Winston said this or Winston said that.

In terms of real people that I use, Klaus Barbie is a very good example. ‘Agent In The Shadows’ was set in 42/43 to the end of the war, in Lyon. So anyone that will know anything about it will know that Klaus Barbie ‘The Butcher of Lyon’ was brought into run the Gestapo there. If I’d created a character modelled on Klaus Barbie it would have felt odd. So I thought in that case I’ve got to use him. In terms of tone I don’t think I said anything that Barbie was unlikely to have said. I just go with it and use my judgment. I always have an author’s note at the end where I flag up what is real and what isn’t real in the book.

There’s a dry humour that underpins Every Spy a Traitor. One of the characters, Charles Cooper, even has the codename ‘Bertie’, which he hopes isn’t a reference to Bertie Worcester. I was wondering if you drew much influence from P.G. Woodhouse and other writers from the 1930s like Evelyn Waugh and Eric Ambler?

No I don’t think so, I haven’t read a lot of 1930s stuff, one or two Somerset Maugham. I like to feel that’s my own voice. I like to have a bit of humour, its difficult too much humour in an espionage novel. Cooper is a little bit of an innocent abroad and I wanted to reflect that. I don’t think I was particularly trying to copy a 1930s dialogue, but I try and write in that time. I’m not a big fan of that era although I do think Eric Ambler is a great writer.

I wouldn’t take any inspiration from P.G. Woodhouse because I think he was a traitor. He was a Nazi collaborator and he should have been punished at the end of the war. The guy collaborated with the Nazis he appeared on Berlin radio. I’m not saying he was a Nazi or a spy but he was certainly a collaborator.

There is a lot of trade craft and interrogation techniques portrayed in your books, how much of it is based on research and how much of it is artistic license?

I do a lot of research, I read about it and talk to some people in that world, although I’ve never been in it myself. Then some of it is me going for it. I think about it quite a lot, because it must be such an extraordinary existence that they’re leading, this kind of clandestine life. I sometimes think about it walking down the street you see other people and you have no idea what they’re going through or thinking. By and large people are fairly impassive and don’t wear their hearts on their sleeve. If you’re working in the world of espionage it’s like that the whole time. It’s all consuming and I imagine what it must be like and the pressures that brings. One mistake and you’re potentially done for, so having to keep up that degree of pretence.

Every Spy a Traitor is your 12th novel, how do you manage to be so prolific, and does the writing ever get any easier?

I start with the story and roughly know where I’m going. You have to know where you’re aiming at and then let how you get there develop organically. You’ve got to be loose enough to let characters emerge and then as they emerge develop in their own way. I wouldn’t say it gets easier, but I don’t think it gets harder. The key thing is getting into the groove. I found the book I’m writing at the moment difficult to start with, but I went to Hamburg to do some research. When I came back I was ready to go. I find writing is like reading, if you’re reading a really good book you want to keep reading it and you want to turn the page over. In that sense I don’t find writing hard.

A lot of it is to do with the process. I think that writing a series brings up a lot of challenges. First book is fine the fourth book is fine, but the second and third books are very difficult, because you’ve got to think ahead, and you’ve got to think back as well. You’re constantly referring back and are constantly making plans because what you can’t do is have something happen halfway through book two that you bitterly regret towards the end of book three, or into book four.

So, there’s a lot of process around it there’s a lot of planning and I try to have intricate plots, three or four storylines that come together and that’s a complex way of writing; particularly as I might write three or four different chapters at the same time, to cover a particular storyline. I might write chapters 8, 11 and 14 first. Its Juggling especially with espionage, you have to keep quite a lot of things up in the air and that’s a difficult thing to do whilst keeping the reader satisfied that they’re actually reading a book. That’s the less fun part, but when you’re really into a chapter and it’s all coming together nicely it’s just brilliant. So, I don’t think I would say it becomes easier every book is a challenge.

Every Spy a Traitor is the first in a new ‘Double Agent’ series, could you tell us a bit more about Book Two?

Book Two is the one I’m writing at the moment and it carries on with the main characters, we still don’t know who Archie is obviously. The core of the story is Operation Sea Lion, the planned German invasion of this country. The plans were fairly advanced and it works well for the plot because the Russians wanted the Germans distracted. Deep down most of the Russians, not Stalin, knew that sooner or later Germany would turn Eastwards and pay attention to them. So Operation Sea Lion was in their interests and it was in Churchill’s interests as well. The threat of invasion was something Churchill could plug into, he took over remember as Prime Minister at a very bad time. There’d been Dunkirk and the defeat in Norway. Hitler had swept all before him. So Churchill could use the threat of invasion to really concentrate people’s minds in this country and that was very important.

Alex Gerlis is the author of Every Spy A Traitor. Alan Bardos is the author of Rising Tide.