Though The Order of the Phoenix is the longest of the six published Potter novels, the production was the shortest, because Dan could devote more time to filming after leaving City of London School last summer, midway through the shoot. He was gobsmacked by his results: As in all three of his AS level exams (religion and philosophy, history, English literature). But he won't be going to university; he's not even sure when - or if - he'll go back to take his A-levels. 'I'm much more into the idea of educating myself just by reading endlessly, which I'm perfectly happy to do,' he grins. His current reading matter: Nabokov's Laughter in the Dark. 'Much easier than Lolita, actually.'

Phoenix is the darkest, most intense, most complex Potter film so far. 'It was also the most fun I've had on any of them,' he says. Not because there are love/kissing scenes - 'although they were good!' - but because he's a big fan of director David Yates. And because he got to work intently with Oldman (Sirius Black) and Staunton (Dolores Umbridge).

Dan is remarkably mature and confident for someone not yet legally an adult. Even with his fine line in luvvie-speak he's the least bumptious, most charming teenage millionaire superstar you're ever likely to meet. 'Someone recently thought I was 19, despite my diminutive stature [he's 5ft 5in],' he says proudly. 'That was quite cool. I must just exude a halo of maturity at all times,' he declaims with a mock theatrical ponceyness.

David Heyman, producer of the Potter films, says that the seventh and final film will be done by 2010. But by 2010, Dan will be 20. Is he committed to the seventh Potter film? For once, his easy conversational flow falters. 'Um, nnnnot for cer ... sure. But if I did the sixth one, which I probably will, I think it'll be really weird not to do the last one. If you've come that far you might as well finish them.'