The American obsession with 'Downton' amuses me slightly because it's such a fiction. I've always been questioned about my historical veracity, and 'Downton' just flies past, when it's completely made up.

I wasn't setting out to write a documentary; if I had, I would have done it in a completely different way. I was asked to write a drama that would appeal to a big audience in America that had no knowledge or interest in The Tudors at all.

The key for me with historical characters is they're interesting because they're human beings. A little bit of Hemingway goes a long way here, but journalists and writers should honestly look at their material and have a real interest, a real passion in what they want to write, and they should also have a lot of knowledge as well.

When you're making a TV drama, the showrunner is God, and so however onerous and difficult and consuming that responsibility is, you're being treated with respect, so it changes your whole outlook to the production. You're being asked about costumes, set design, music, every aspect of the show.