Few first-time British film directors get to cut their teeth on a production on the scale of Testament of Youth, which lavishly returns us to the halcyon early summer of 1914 and then to the grim moment when war broke out across Europe.

The story begins in a sunny Derbyshire, where the strong-willed young Vera Brittain (played with an impeccable English accent by Swedish actor Alicia Vikander) is busy petitioning her traditionalist father to allow her to apply for Oxford.

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It’s a battle she will win, only for her to abandon her academic aspirations with the war’s outbreak. Compelled instead to volunteer as a nurse, she experiences first-hand the graphic after-effects of the conflict, while bearing personal witness to the war’s toll on a generation of young men, many of whom never returned home.

At the helm of this first big-screen adaptation of Brittain’s celebrated First World War memoir (a much-loved BBC miniseries aired in 1979) was James Kent, who comes to cinema after a career in TV documentary and drama – including, most recently, The White Queen and The Thirteenth Tale for BBC2.

With a week to go until the film’s release, we sat down with the director to discuss the challenges of first-time filmmaking and the responsibility of doing justice to the work of one of the Great War’s most affecting chroniclers.

James Kent

This is your first feature film after a career in television. Were you looking around for a feature film to direct, or did this happen to come your way?

I secretly hoped one day I’d get to direct a feature film, because I’ve done so much documentary and drama in television. Television was my first love, but there’s a limit on the budget and on the status of the director – it’s very writer-led.

One of the Heyday Films producers, Rosie Alison, knew my work; we have a shared sensibility on the world. So I went to Rosie and David [Heyman] with several pitches. I got through that, then it was a case of pitching to Ben [Roberts] and Natascha [Wharton] at the BFI and Christine Langan at the BBC.

It’s a lot of work to become attached to a film – a first film, budgeted at £7m, that doesn’t have any megastars in it. For Heyday, the combination of Ang Lee and Testament of Youth would have meant it went straight into production. But James Kent and the cast of Testament of Youth – it’s just a harder deal. I’m absolutely thrilled now that I’ve made it, and want to make another one!

What drew you to this script?

Its emotional intensity. I naturally gravitate towards women’s stories; I’ve done a number of television dramas about women – Margaret Thatcher [in 2009’s Margaret]; a Georgian lesbian, Anne Lister [in 2010’s The Secret Diaries of Miss Anne Lister]. Because they’ve had greater obstacles to confront in the past, women often have some of the best stories. Also there’s a massive female audience out there who aren’t being catered for.

I went to Oxford, like Vera. And I come from Yorkshire, which is close to Derbyshire. So there are certain elements of Vera’s life which intersect with my own.

Testament of Youth (2014)

Had you read her memoir before?

No, but as a teenager I saw the TV series with Cheryl Campbell, which won the BAFTA for 1979. I watched it again this time last year, when we were just beginning the preparations for the film. With limited results. You take away some of Vera’s intrinsic qualities, but at the same time it’s quite dated. Her feistiness is heightened on camera, but it’s not a particularly beautiful or cinematic production – but it was television circa 1979, which was generally neither of those things.

While relatively low-budget, you were still working on a bigger scale than many first-time film directors in the UK can manage. What was it like arriving on set on the first day?

To be absolutely honest, in this respect it doesn’t feel that different from high-end television, because high-end television has large budgets and the set doesn’t look so different. What is different is what’s at stake. A film is here for quite a long time and you need to account for that film. I had no concept before this of what it was to publicise a film. The film has been really well received, but I don’t know what it must be like to sit here and talk about a film that’s been universally panned. When I look back, I understand why my producers were so exacting – there’s no escape from what you’ve shot.

How easy was it to assemble the right cast?

Being an unknown director in film makes it a bigger deal trying to woo actors, but Alicia wanted very much to do the part, as did Kit Harington [who plays Vera’s paramour, Roland]. The big advantage is that with young people they really want to do the film; the experience of the director isn’t their top priority. Their top priority is whether they love the part and whether it’s going to provide a showcase or stretch them.

For Alicia, it gave her a major English-language film that she could dominate, and for Kit, frankly, it wasn’t Game of Thrones, it was a serious part. For Colin Morgan, it was his first big film after coming out of Merlin, while for Taron Egerton [Vera’s brother, Edward], he’d only been out of RADA for less than a year.

There’s something additionally poignant about this young generation of up-and-coming actors playing a generation of men whose promise was wasted.

I hadn’t thought of that. So their present-day potential casts an interesting hindsight on the potential of these young men who were denied potential? Yes, that’s interesting.

You’ve said making films and high-end television are quite similar, but were there moments when you had to stop yourself and think “no, I shouldn’t do it like this, I should do it like that, because this is cinema”?

Yes, there’s a bigger world you’ve got to show. There has to be the epic in the intimate. So there’s the big scene at the train station when Roland says goodbye, the scene with the stretchers in the field of wounded, the Oxford high street with the carriages and bustle of people – you have to have those moments when the audience is getting the world proper. You need those moments to deliver or it’s just too chamber piece.

Testament of Youth (2014)

That terrific crane shot over the field of wounded is presumably a conscious homage to the shot of Vivien Leigh walking among the wounded in Gone with the Wind (1939)?

It is! I thought: why not? In a way it’s rather lovely to flow back to the 1930s. Filmmakers cross-reference each other all the time. The other film I referenced is Brief Encounter (1945), which I’m ashamed to say I saw for the first time while preparing this film – and I’m 50!

But I loved it, and the intensity of Celia Johnson’s train scenes when she’s got that internal questioning monologue and the gossiping train companions. That fed into some of the train scenes in Testament of Youth.

The film is coming out at the time of the centenary of the First World War, but do you think it will speak to young people living 100 years later?

We shall see. Obviously there’s a fanbase out there for some of our young cast. But I think particularly young women and girls will understand what this film’s about. Brittain’s book largely spoke to women when they were young – it was at its height in the 60s and 70s, when it was reissued and there was the television series. What I hope women will love about this film, as they loved about the book and the TV series, is its unapologetic emotional attitude to what it’s like to be a young girl. As with Cathy in Wuthering Heights, they can live their own troubles through Vera’s troubles. It’s a great love story and great love stories speak to any age.

Testament of Youth (2014)

What’s the key moment in the film for you?

The most pivotal scene is when Vera is nursing a dying German officer and she has to pretend to be Clara, his girlfriend, because he thinks his girlfriend is by his bedside. In that moment, Vera really realises that – German or British – you are ‘boyfriend’, you are ‘son’, you are someone’s brother. It’s an incredibly beautiful scene, brilliantly played both by Alicia and by Adam Ganne, who plays the German officer – it’s difficult to play ‘dying’ but he does a brilliant job.

A director, Susanna White, told me that she felt that if you cast a film correctly then 60%-70% of a director’s job is done. It doesn’t have to look beautiful or have amazing music. If the performances are amazing, it’ll be a pretty damn good film whatever happens.

This is a film that does look beautiful though, both in terms of its actors and its production values. The depiction of the Edwardian era just prior to the outbreak of the war is idyllic …

No one comes to this film not knowing [that war is going to interrupt these scenes]. So even the beauty is an ironic beauty; you know that they’re living a kind of fantasy youth that’s going to be completely destroyed by the decisions of their elders. It was a famously glorious summer, and Vera lives in a beautiful part of the world, Derbyshire, so it’s hard to make that not beautiful – but it was intentional to make it seem almost fantastical.

Testament of Youth (2014)

For a filmmaker to get a mainstream audience into a film, if it’s a harrowing film, you have to offer a way out for people. One of the things I could do was to make it at least a beautiful film so that they could sink into it without thinking: Oh my God, is it going to be two hours of this?

Occasionally a film breaks through from that rule, like I would say 12 Years a Slave (2013) or Schindler’s List (1993) did. But a lot of films fail to win the love of their audience because they push them too hard. People don’t want that; they want to have an experience that’s meaningful and important but not one that drains them dry. So make those images cinematic and immersive.

That said, you don’t see images of conflict and violence in the film, you just see the after-effects of the conflict.

The reason for that is that Vera didn’t. My rule was: what does she see? She can imagine Roland in the trench and Edward in the trench, because they write to her. But they don’t write to her about the woundings, they don’t want her to know about them – they’re very protective. What she sees are the mass maimings as soldiers are brought into the hospitals. That we do show. Just enough to let you know what her environment was like.

Actors Taron Egerton, Kit Harington, producer Rosie Alison, director James Kent and actor Colin Morgan attend the photocall for Testament of Youth (2014) during the 58th BFI London Film Festival

The film premiered at last year’s London Film Festival. Were you pleased with how it went down?

Really pleased. It was a huge boost for the film that we were chosen as the Centrepiece Gala. It was perfect timing: we’d made a very British film in the centennial year of the war, and we’d finished the film three days before the festival!

Testament of Youth was backed by the BFI Film Fund. The film received its world premiere as the Centrepiece Gala of the 58th BFI London Film Festival.