List: Ironclad is another historical film, after Solomon Kane and your part as Mark Antony in HBO’s Rome. What draws you to these parts?

JP: It could just be what I’m getting offered. I try to take every script on it’s own merit, and if it happens to be a historical film, it’s not like I’m trying to corner the market on ‘sword movies’. If I think if the script’s good, the director’s interesting, the other people involved are interesting, then it’s likely I’ll do it.

List: And you’ve done other period films that aren’t ‘sword movies’.

JP: Yeah, Vanity Fair was one, some Shakespearian theatre. It sort of depends what you’ve seen, really. I did a series for NBC last year called The Philanthropist which was about a billionaire philanthropist, who was a real guy, and we shot about eight episodes of that, so that was, you know, suits and mobiles phones. Unfortunately, I’ve no idea if it’s coming out over here!

List: Paul Giamatti plays the English king in Ironclad…

JP: He’s terrific! I think Paul really relished the part – normally, he does incredibly understated performances that are very subtle, but this film required him to be something else entirely, and we don’t just get the wicked, cartoon version of King John – we get the living, breathing thug to end all thugs. He’s just appalling. I think it’s quite refreshing, to tell the honest truth, to see a member of the royal family being portrayed so unsympathetically –

List: Especially straight off the back of The King’s Speech

JP: Exactly. I think it makes us realise that the people sitting in Buckingham Palace now are descendants of thugs and gangsters.

List: And does his accent hold up?

JP: Oh yes, completely!

List: Because there’s a tendency in historical movies to go one of three ways: everyone does a real accent, or everyone does the same fake accent, or no one really bothers with it at all.

JP: I always think it’s a really difficult one because, we obviously have no idea how those people spoke.

List: Jonathan English [director of Ironclad] has likened the film to a medieval Magnificent Seven –

JP: Well, yeah, there certainly is a very strong element of that – and why not? It’s a magnificent template for a film. We love those stories. And of course, Magnificent Seven wasn’t the first Magnificent Seven, It was the Seven Samurai before that, and probably many others before that. It’s one of the classic stories, isn’t it? There’s only seven stories, and that’s one of them.

List: Were there any other films you had in mind while making it?

JP: I guess Braveheart, certainly in its depiction of violence – this is an incredibly violent film. Not a glorification of violence, by any stretch of the imagination. My overwhelming feeling when I saw it was, ‘That really probably is what it was like, to be in a really brutal medieval siege.’ And no punches are pulled. This isn’t tea-time Robin Hood on the BBC. This is probably as close to being in a medieval siege as anybody’s going to get.

List: And do you know what certificate is being aimed for?

JP: I actually have no idea – I feel like I should know that! If it isn’t an 18, there’s something terribly wrong with our value system. I was certainly very aware that Solomon Kane, which has moments of extreme violence as well, that the DVD sales far outstripped the cinema seats that were sold, and I suspect that’s largely to do with 13, 14 year old boys getting someone to buy the movie for them that they couldn’t see at the cinema.

List: Mackenzie Crook joined you from Solomon Kane for Ironclad.

JP: Yeah, this is the second time I’ve worked with Mackenzie, and they’re both incredibly different characters. One was a mad gothic priest, and this time he’s very sexy, as a brilliant archer. He’s our bowman in the film – each of them have a skill, if you like. He just looks very sexy, very cool.

List: Can you see that as a route that he’ll travel down now?

JP: I would hope so, as he’ll make a lot of money from it!

List: The swashbuckling nature he’s going for was sort of hinted at in the Pirates of the Caribbean films, although he had more of a comedy role.

JP: Oh, he doesn’t do any comedy in this one. He just looks rough and tousled, and yeah, sexy.

List: Your character is subject to numerous vows.

JP: Yes – he’s a Templar Knight, and his name is Sir Thomas Marshall – which is nothing to do with a knight called William Marshall, who was around at the time – this one’s a fictitious character, and he’s a Templar Knight. The Templar Knights were very severe men: they were warrior monks, they were trained in the art of warfare from a very young age, and they had to take the three vows: one of chastity, one of poverty, and one of obedience.

List: And how long does he uphold these vows in the film?

JP: Well, he tries as hard as he possibly can! One of the things to do with his character is that he’s committed a lot of atrocities in the name of God, in the Holy Land, but because he is a Templar Knight, he is protected by any kind of payback from God, because he’s doing it in God’s name. He’s committed these atrocities, and now he has a great sense of betrayal by the church, because he knows in his heart of hearts that what he did was wrong, and when we meet him at the beginning of the film, he’s already wavering as to whether he feels he should keep being a Templar Knight or not. So by the time he meets the Lady Isobel [played in the film by Kate Mara, recently seen in 127 Hours], those vows are already being compromised to a certain degree. So I guess he figures, once he’s broken one of them, he might as well go for all three!

What I found fascinating about him was, this is a film that takes place 400 years before Solomon Kane, and as a result of that, this is a man who has no sense of writing, or culture, or art – any of those things. So one of the things that I found very interesting when playing him is, what goes through a man’s mind when he’s had no access at all to the world, in any kind of cultural sense? The only thing he knows about is the Bible.

List: One last question then, on the weather. The film started filming in Wales, in the lead up to winter

JP: Yep. Driving rain. But frankly, you know – I’ve done Solomon Kane! In temperatures of minus ten degrees for four months.

List: There could be the argument that the weather enhanced the performances – for example, Paul Giamatti, standing in the pouring rain, is going to feel some of the discomfort of a medieval king in wartime, but as a veteran of Solomon Kane, you might be more immune

JP: Yeah – ‘Come on guys, don’t be such a bunch of pussies.’ Absolutely! This is just Wales. It’s temperate rain. I mean, yes, it was driving rain, and the set deteriorated terribly over the 11 weeks that we were there – because it was pretty much shot on one set – and it became dangerous and very muddy, but really, it was just a bit of mud.

Ironclad stars James Purefoy, Paul Giamatti, Brian Cox, Mackenzie Crook and Kate Mara, and will be released on Friday 4 March.