Talk about symbolic. It’s the end of a long day’s location shoot on the Harry Potter franchise. Total Film is sat yakking with the series’ now-signature director, David Yates, in a dressing tent. Suddenly, it all goes inky-black.

Just one of the crew powering down the lights for the day. Fitting metaphor, though, for a saga that gets darker with every episode, right?

“For me, this is a warmer, lighter film than Order Of The Phoenix,” says Yates.“I loved the intensity of the fifth one, but it had all this bloody earnest teenage-angst stuff, whereas this is a little bit more of a romantic comedy – until things turn dark in the third act…”

We’ll get back to that. In the meantime, hormones are off the hook at Hogwarts: “There’s a lot to do with Ron and Hermione’s relationship in this one,” says Emma Watson.

“Which is great, because it gave us the chance to do comedy. Hermione got very serious in the last couple, so it was nice to do some funny bits with Rupert [Grint], who’s great at that sort of thing.”

But slightly awkward when it comes to love scenes, mind. “There’s a bit of a kiss with Jessie [Cave, who plays Lavender], which was quite embarrassing,” confesses Rupert Grint.

“That particular scene, I hadn’t known Jessie that long and there were loads of people around; it’s after the Quidditch match and I was standing on a little plinth, so it wasn’t really that romantic!”

Quidditch match? Yes – it’s back. “The technology has moved on so we’ve made some refinements,” grins Yates. “I was always intrigued by how violent Quidditch could be. You’ve got these players moving at enormous speed and crashing into each other… It’s a bit like American football, which got me excited.”

But it’s not all fun and games. Or loveydovey. At heart, Half-Blood Prince is all about getting prepped for the final showdown between wizards good and bad.

“Number six is kind of the hardest book to film,” reflects Harry’s alter ego Daniel Radcliffe, looking distinctly un-wizardly in chunky winter casuals and without specs.

“It’s a great book, really exciting, but also very much a lead-up to the seventh one. There’s a lot of exposition that has to go on, but they’ve done a really good job.”