I can worry about anything.

I actually had that conversation with [Channel 4 Chief Creative Officer] Jay Hunt. We were at a bit of a crisis point. I'd written a totally different script - about war, basically - that got rejected at the last minute for various reasons. The whole of the series was in doubt. I said, "Well, there is one other idea ["National Anthem"]."

I think people are starting to look away and questioning, and they're sort of horrified.

You don't have the economy of scale of building a set once and casting once. You blow up the world, basically, at the end of each episode.

"National Anthem" was just a funny idea I'd been knocking about. I initially thought about a beloved celebrity having to do that - and then I watched an episode of 24. In my head, I was writing almost a parody of a 24-style president woken in the middle of the night with a crisis. It seemed more interesting to play it ultrastraight and to have the viewer's initial reaction be one of laughter and disbelief - and just have the whole thing become progressively more uncomfortable.

You sort of perform your personality, I guess, to everyone on some level.

If love were a product, the queue at the faulty goods desk would stretch right round the universe and back. It doesn't work properly. The seams come apart and it's full of powdered glass.