With the new one-off spy story Legacy set to air on BBC Two later this month, Dublin actor Andrew Scott has been talking about his role in the Cold War thriller.

Based on the Alan Judd book of the same name, Legacy also stars Charlie Cox, Romola Garai and Simon Russell Beale and has been adapted for television by award-winning writer Paula Milne, whose credits include The Politician's Husband and White Heat.

Set in 1974, Legacy tells the story of a trainee British spy, Charles Thoroughgood (Cox).

Scott plays Viktor Koslov, a Russian diplomat who Thoroughgood knew at university and who MI6 want their new recruit to 'turn'.

Here, Sherlock star Scott talks about why he chose the project, and what viewers can expect.

What attracted you to Legacy?

Andrew Scott: The thing that was most attractive to me to Legacy was its director, Pete Travis. He had directed a film on Omagh, which I thought was a brilliant film, and I went to meet with him and he spoke very eloquently about Omagh. My family are from Omagh and it's a very delicate matter, about the Omagh bomb, so that meant an awful lot to me. I remember thinking it was so beautifully handled. So the most exciting thing about Legacy was to get to work with Pete and he didn't disappoint.

How would you describe your character Viktor?

He's quite a conflicted character. The movie deals a lot with friendship and what it means when two friends are on different sides of the political spectrum. So an interesting thing about playing Viktor was the conflict within him about what he has to do, what his job requires him to do and what his friendship with Charles requires him to do as well. He's a very talented and intelligent person and he's definitely a family man. He's a little lonely as well.

The nature of their relationship is that Viktor and Charles are constantly crossing and double crossing one another. What was that like to play?

We spoke a lot about that. It's not difficult to play if you just play one thing, if you start playing lots of different things at the same time it becomes overcomplicated. The spy stuff takes care of itself, you don't want to patronise the audience too much. You just play the friendship straight down the middle, not suspicious eyes and long lingering looks as that reduces the story somewhat. You need to play it as simply as possible, the plot takes care of itself.

What was it like having to learn a Russian accent?
That was probably the biggest challenge of it. You don't hear a lot of Russian people speaking English, particularly in the 1970s. You have to try and move away from the Bond villain stereotype. It's a very particular way of speaking and a very particular rhythm. I had a really fantastic dialect coach that I worked very well with and I was constantly surprised by the different intonations that the Russian dialect has.

It's a whole new way of thinking, one has to try and imagine what it's like to speak English as a second language and make the character one's own. That was the biggest challenge in playing him, he's got a very unusual way of talking but that just has to be embraced. At the beginning Pete and I talked about how Russian he should be and I think it's very important that we fully embrace his Russianness and don't shy away from it, which meant that it was very important that I submerse myself in as many Russian videos and tapes as possible.

Did you do any research into the Cold War for the role?

Yes. We had a really interesting guy come to talk to us, a retired spy, so we had a sort of spy school. He spoke to us about the nature of being a spy in the 1970s and 1980s and it was really fascinating to listen to. What was interesting to me was what it was like to be a spy so I asked him questions about what effect it had on his family and the people around him. Spies get very close within their own circle because it's a thrill that they share and a secret that they share, which I think means that everyone else can be excluded somewhat. There's a bit of a trench mentality.

It must be a difficult thing living with those secrets and seeing the things that they see. That's what was really interesting stuff for me, the psychological effect that being a spy would have on our characters. The spy element is really interesting and I think that's great fun for the audience, but at the heart of Legacy is what being a spy does to families and friendships.

Did you read the novel before you started filming?

No. My character is quite different to the novel and I'm one of those guys that feel that you've got to play what the script is, and it's been adapted so brilliantly. My job is to bring the script to life as much as possible so I didn't read the book, intentionally. I stuck with the story within our script.

Is the genre one that you enjoy watching yourself?

Absolutely. I enjoy spy movies and Tinker Tailor Solider Spy, for example, is great. I've never been in anything like this before so it was really nice to look at what Pete (director) was doing visually. I think he's really created the feeling of the 1970s and that grimy London feel. A lot of the camera work is handheld and it's almost documentary style in places which is really interesting. It's brilliant that there are dramas like this on BBC Two that give you that great freedom for it to have a particular style.

Why do you think audiences enjoy espionage thrillers so much?

I suppose it's an escape really. It's a thrilling world and people really like stories about secrets, which is the essence of a spy drama. It's the essence of all drama really, whether you're hiding a secret or revealing a secret, whether it's a period drama or a spy drama. In a good drama there's a secret at the centre of it, which can be pushed further in a spy drama. Audiences like to be challenged and to be actively involved and try to guess an outcome. Plus everyone likes to think they could be a spy.

Was there a scene you particularly enjoyed playing?
One of the other reasons I was so happy to be involved in Legacy was the cast. Most of my stuff was with Charlie Cox, who is an actor I have admired for a long time. We had to do a lot of night shoots and we had a great laugh over the hot summer when we shot it. The great pleasure in playing Viktor was playing that friendship and that was the most fun for me. Also the fact that Romola is in it, we've worked together on The Hour, and I think she's a formidable actress. Simon Russell Beale is a real hero. That was really the most fun part for me, getting to work with all the other actors.

Legacy's time and date of broadcast have yet to be announced.