I’ve always had this story in mind, and when you discover what it is, you’ll go, ‘Oh, right...’ You’ll see how that can spread out [for ten episodes]. Actually, Children Of Earth could have run for ten episodes. Once you get martial law declared, we could have done three more episodes of that - if anything, we slightly rushed that ending. So this story is on that big a scale. It’s not a Lost-type story, full of mystery, and it’s not particularly complicated - it’s more linear. Ten parts just gives us a chance to move it onto the international stage where it takes place. The vast majority’s going to take place in America - and other countries as well - so it's got a size to it. It’s a proper, big, global ten-hour thriller.