"There is a deeply compelling story here that, with a few more risks taken by the filmmakers, could have been fully realised"

2015 looks set to be the year that Alicia Vikander becomes a star, and if you don't know much about her yet, you're bound to soon enough. The Swedish actress has seven (!) films slated for release this year -- three in January alone, the first of which sees her play feminist writer Vera Brittain in Testament of Youth, a strongly acted but disappointingly uninspiring period drama.

Based on Brittain's classic autobiography about her time serving as a nurse during World War I, Testament of Youth sees experienced TV director James Kent making his first jump into feature films.

At the end of the First World War, Vera Brittain was just 24, and like many her age; she had experienced more grief than most do in a lifetime. When her account of this period was published years later, it was heralded as a classic of feminist and pacifist literature, highlighting the struggles that women faced in the pre and post-war years. This adaptation follows Brittain's transformation during the war, from rebellious teen, to impassioned campaigner, focusing on her doomed romance with poet and soldier Roland Leighton (Game of Thrones' Kit Harington).

Vikander turns in a stunningly intelligent performance, one that is rich in nuanced emotion. Her Brittain feels far closer to a living, breathing character than most heroines do in a lot of period dramas, because rather than wearing her heart on her sleeve, her inner turmoil is hidden behind a mask of intricate facial expressions.

The supporting cast give a more mixed set of performances. The experienced Dominic West and Emily Watson are solid, if not slightly hammy, as Brittain's parents, but a slew of young British actors provide little excitement. There's nothing terribly wrong with them, they just come off as a little wet.

On paper, Testament of Youth should be stronger than it is. It's beautifully framed, par for the course when it comes to period drama, and has a rich score composed by Max Richter. It covers a cornucopia of themes ranging from lost love, intolerance of educated women, to the horrific impact that war can have on all walks of society.

Sadly, the narrative never feels quite strong enough to carry all these elements and more often than not, the film feels dull and even sluggish. It becomes frustrating when, for the thousandth time, they try to drive home the fact that war is, as you’ve no doubt guessed, not very pleasant.

Therein lies Testament of Youth's problem. Brittain took 17 years to write about her experiences of the Great War, campaigning heavily for peace during this time. There are fleeting moments of this passion, including the film's emotional denouement, but they are few and far between. The rest of the film feels a little too tame, never really pushing its themes hard enough to be truly interesting.

There is a deeply compelling story here that, with a few more risks taken by the filmmakers, could have been fully realised.