13/03/2012 19:06 GMT | Updated 13/05/2012 06:12 BST

Adapting Jane Eyre for the Big Screen

It's a daunting thing, adapting one of the most beloved novels in the world. Jane Eyre is a lifelong friend to many people. Like all great classics, it reveals different things at every reading. I would not have attempted it had I not loved the novel so much myself. I thought it an irresistible opportunity to introduce the book to those who have not yet had the pleasure and to make the familiar fresh and alive to those who have.

That's not to say I didn't lose sleep, sitting down to distill its 700 pages into a hopefully vivid, actor-friendly 99-page screenplay.

Jane Eyre is the orphan who manages to sustain herself without family, without money and without love. She has been told that she is ugly and full of wickedness. Yet she values herself. She is not meekly accepting of her lot. She feels injustice keenly. She is quietly defiant. She holds, for a girl of her time, quite radical ideas about equality. It is her courage, wit and her wry humour that makes us love Jane Eyre.

This fiery, lonely spirit finds herself in the middle of a Gothic thriller. She is employed as a governess by Edward Fairfax Rochester. Thus begins one of the greatest romances ever written. All these elements must be honoured in an adaptation; the book's still urgent politics, the Gothic haunted house and the complexity of the love story. I threw myself in, relying on instinct as much as anything, trying not to get bogged down with the book's critical heritage. Faithfully adapting all the major scenes, I soon realised that the structure of the book would not translate to film. The year that Jane spends with the Rivers family is very important, but in a film it comes 20 minutes away from the end - a terrible time to start introducing major new characters. So I put it at the top. It gave me the ability to jump from her present to her past; to be selective with the way I told the story - just as memory is selective.

I wanted to honour Charlotte Bronte's poetic language. I modernised slightly but tried to keep true to Jane and Rochester's wonderful articulacy. These two people fascinate each other with words. They talk each other into love. One of the scenes I am most proud of is their first at Rochester's fireside, beautifully played by Mia Wasikowska and Michael Fassbender. Some of the lines are Bronte's and some are mine. I think the skill of the adaptor is to make the joins invisible.

But a screenplay must be more than just dialogue. I thought of Jane Eyre the artist; how vividly she sees and describes her world. I tried to give the script a strong visual flavour. This was taken up and enriched admirably by Cary Fukanaka our director and Adriano Goldman our cinematographer. I love the film's harsh winter beauty, the use of natural light and the way expression is trusted to tell the story. The shape of each character is defined by Michael O'Connor's superb costumes and the emotional journey heightened by Dario Marinelli's score. I was especially delighted that it was shot in Derbyshire, a landscape I know and love, where Charlotte Bronte wrote much of the book.

There are many omissions in this adaptation. But I hope it is true to the spirit of the book. I remember the impact Jane Eyre had on me when I first read it in my teens. It is my teenage self I was writing for. We felt it very important to cast an actress as young as Jane herself. Mia was just 19 when the film was shot. She captures perfectly that brave young mind, that undaunted spirit who manages to value herself despite the damage she has suffered and who teaches us to cry, "equal, as we are!"

Jane Eyre starring Michael Fassbender, Dame Judi Dench and Mia Wasikoswka is out on Blu-Ray and DVD now.