Do you think the writers lend an American favour to the dialogue, or is it authentically British?

It doesn't matter. It's better if it's something that sounds like we would speak today, because for those people living then it didn't sound like 'old' English, did it? I suppose it's better that we have those little Americanisations, like saying 'Yeah.' I don't think a very high-class English person would have said, 'Yeah,' but it doesn't really matter.

I had a couple of lines yesterday that I thought, 'Do you mind if it sounds a bit American?' They didn't, and I don't either. It's fine, as long as the audience don't think, 'That's suddenly American.'