After working to crack codes during WWII at Bletchley Park, four women reunite years later to use their skills to track down a serial killer in London during the early Fifties. William And Mary star Julie Graham plays Jean, who teams up with old colleagues Susan (Anna Maxwell Martin), Millie (Rachael Stirling), and Lucy (Sophie Rundle), in ITV1's The Bletchley Circle…

Do you find this period, the early Fifties, appealing?
In terms of feminism I think it’s an amazing period because obviously women were useful and worked during the war, and then had to go back to these quite terribly mundane lives where they weren’t listened to afterwards. There was no importance — it must have been really hard for them to do that. I think some probably adjusted better than others. Someone like Jean probably did adjust better then someone like Susan, who was incredibly bright, and suddenly she’s a housewife with two children and no prospect of doing anything else except being a mother and a wife.

How would you describe Jean? Is she the sort of person on the surface you’d underestimate, but is capable of great bravery and strength?
Yes, I think all those women are to a certain extent. They’re all so different but really at their core they are incredibly resolute at what they’re going to do.

It’s interesting having four female sleuths as the leads in The Bletchley Circle…
When something is set in a period like this, women can just get away with so much more. You know that kind of lovely thing with Marple where she’s not actually a detective but she pokes her nose in and the police are very disparaging of her, and of course she’s a genius but she’s a little old lady as well.

The thing I loved about the scripts when I first read them was I thought it was a gripping story but I loved the characters. I thought all the characters were really well drawn and characters you don’t really see on television very much — women of that age and women of that class.

Did you do much research before filming The Bletchley Circle?
Well I read quite a lot about Bletchley. I think there’s this endless documentation about Bletchley, and strangely enough it wasn’t until the early Eighties that women were even mentioned in the books.

Oh really?
Yes, for a long time, it was only recently that it has been picked up.

They probably couldn’t talk about it could they?
No. It was really good in terms of my research because there’s a great website connected to Bletchley where these women talk about what it was like. The day to day methods and the day to day grind, and actually how mundane and boring it was. I just read a lot of stuff and looked at a lot of pictures to get the feel of it, and it was all very sparse. I didn’t actually get to go to Bletchley because I was doing another job and I didn’t have enough time.

Does the drama have a real sense of camaraderie and coming together?
Yes it’s not bleak at all, it’s a real roller coaster. When I read it I was gripped immediately because you’ve got this backstory as well of all these girls being killed, and so it’s very gripping. We’re not making a documentary about life after Bletchley, it’s very much a story of four women against the odds.

Do you think it’s a job that you could do for real? Is it something that appeals now that you’ve done this?
What a librarian?

No! A spy — a librarian as well, if you want!
The spy bit definitely. Everyone wants to be a spy don’t they?

Are you good at keeping secrets though?
Not really, no! I’m a terrible gossip. I like to think I am. I do that thing where I go, ‘Don’t tell anyone, because I was told not to tell anyone, but I’m just telling you, so you mustn’t tell anyone!' I’d probably be a bit rubbish, to be honest. I’ve always thought I’d make quite a good detective though. I like solving puzzles.

How would you describe the look of the show?
Susan’s house that we filmed in was absolutely authentic, post-war Fifties. Rachael Stirling described the furniture as the opposite of soft furnishings, like you sit down and graze your elbow and everything’s the same colour. The crew found the most amazing location in Croydon where’s there’s this woman who I think had been left this house by her aunt, and she’d left it exactly as it was in the Fifties. It was incredible.

ITV1, Thursday
Ben Lawrence