I'm playing one of the principal roles, which gives you more clout and more confidence.

Because [writers] Dan Weiss and David Benioff have done such a great job in adapting them, that's what we work with. It serves no purpose to anybody for actors to come onto a set with a well-thumbed copy of the source material and start querying why this or that line has been left out of the script. It's probably been left out for a good reason.

I'm playing one of the principal roles, which gives you more clout and more confidence.

Power is always a corrupting influence. In this mythical time - let's call it medieval, feudal - people in power are dictatorial and don't want their positions of power to be threatened.

On an independent film you're lucky if you get one, but ostensibly the job is the same. There's very little difference, apart from the knowledge that there's a captive audience at the end of it - which you can't always guarantee with a movie.

I am made Hand of the King which gives me an enormous amount of power, which I use quite ruthlessly - but skilfully - and Dame Diana Rigg joins us [playing political mastermind the Queen of Thorns] and we have a couple of really good sparring moments.

Most films are written and made with a hero around 35, or even 25.