Kiera Knightley in a moment from Pride & Prejudice

Two Brits are up for the coveted Best Actress award ? Kiera Knightley for Pride & Prejudice and Judi Dench for Mrs Henderson Presents. Here, Deborah Moggach, the screenwriter of Pride & Prejudice, and Iris director Richard Eyre put their crosses in the box.

Deborah Moggach for Keira Knightley

I was so thrilled to see that Keira Knightley has an Oscar nomination for Pride & Prejudice. I would be, wouldn?t I, as I wrote the screenplay. But honestly, I would be rooting for her even if I?d had nothing to do with it, for Keira has done a wonderful job and overcome a seemingly insuperable problem.

The problem, of course, is her beauty. Not the sort of problem that would bother most of us, I daresay, but a bit of a poser when it comes to playing Elizabeth Bennet. For the point of Lizzy is that she?s less beautiful than her older sister Jane ? as Darcy observes at the assembly ball, with staggering tactlessness, she?s not handsome enough to tempt him.

This line could ring rather hollow when the girl in question is drop-dead gorgeous.

The point of Lizzy is that her attraction springs from her wit and intelligence. It?s these qualities that make her sexy, give hope to us all, and that capture the heart of the handsomest man in England who also happens to own half of Derbyshire.

So when Keira was cast I was taken aback. People said: ?Hey, it?s the movies. The heroine?s got to be gorgeous, even if she?s supposed to be plain. Think of Joan Fontaine playing Jane Eyre, for Chrissakes!?

This still didn?t convince me. Then I started to watch the rushes, and saw that Keira was a revelation. For she caught the spirit of Lizzy, her inner light, her larkiness, and inhabited the role with such vivacity and wit that she transcended her looks. She even did the impossible and made us believe that though we might find her irresistible, a conventional man in Austen?s day might not. She would be too natural for his taste; he might indeed prefer the more classical, serene beauty of Jane.

Before I began writing the screenplay I made a decision: this was Lizzy?s story. We would see it all through her eyes, we would go right into her heart.

She would confide in nobody and keep her secrets and catastrophic mistakes to herself. This places a huge burden on an actress, of course, because her turmoil must be interior. But Keira had that transparency ? we can almost feel her thoughts before she does. And as the film was edited everyone recognised that, and started cutting away the scenes that distracted attention from her own inner journey.

The other decision I made was that this story really matters. It?s not a frothy comedy, there?s real turmoil and pain there, and you can see this in Keira?s face. During the big ball scene, for instance, she experiences the most complex sequence of emotions ? embarrassment, desire, humiliation, laughter, pity, irritability, and a sort of wondering awakening to love. And it?s all there; just watch her.

In other words, she?s a star. And we don?t have many of them in this country. So let?s give her an Oscar.

Dame Judi Dench in Mrs Henderson Presents

Richard Eyre for Judi Dench

As an actress, Judi Dench is luminous. It?s difficult to pin her down but I would say that her most defining characteristic is that she manages to be authoritative and witty at the same time.

That is absolutely integral to her allure. To be such a clear authority figure and to still retain the ability and the power to touch your heart, it?s an incredibly difficult trick to pull off. Judi does this better than anyone else; I would say she is uniquely capable of it.

Even when she?s playing a role such as Elizabeth in Shakespeare in Love there?s a kind of roguishness, a larkiness to her, that?s irresistible. There is forever a twinkle in her eye.

I?ve just finished working with Judi on a new film, Notes on a Scandal, from the novel by Zoe Heller, with Cate Blanchett and Bill Nighy. But I?ve worked with her before many, many times on the stage and on film Iris, for which Dench won an Academy Award for Best Supporting Actress, and her methods and her abilities are exactly the same in both mediums.

She doesn?t age as an actress; when you think about it, she has been at the peak of her career for about the past 50 years. It?s difficult to do her credit properly without turning her into a dreary shopping list, but Judi is incredibly direct and honest, she works very hard on the set, she?s loyal and diffident, she completely and utterly lacks airs and graces of any kind, and I think this is because her passion is consuming.

In Mrs Henderson Presents I thought she was magnificent. She so clearly exudes a sense of joy in the role, and what struck me again and again was the wit she managed to convey in her characterisation. She also has incredible control, but what you see on the screen is just her joy and her wit. Of course she ought to win the Oscar, but I don?t think she will ? I think Reese Witherspoon will get it for Walk the Line. But of course it ought to go to Judi. It isn?t even a question.