He says Studio Ghibli has recently built a creche for its staff - and he spends a lot of his time there. 'I look at them and try to see things as they do,' he says. 'If I can do that, I can create universal appeal.' The relationship is two-way, he says. 'We get encouragement and strength from watching children. I consider it a blessing to be able to do that, and to make movies in this chaotic, testing world,' he says.

He says adults face a choice between love and money. 'A five-year-old understands that in a way an adult obsessed with money and share prices cannot. I make movies that can be understood by that five-year-old and to bring out that purity of heart.'

A stiff, avuncular presence in his tweed suit and maths teacher's glasses, Miyazaki is clearly uneasy dealing with the media circus. The 67-year-old's movies are paeans to the natural world and coded warnings about its perilous state; in a recent interview he fondly speculated on a natural disaster that would return the planet to its pristine state.

He spends years buried away in this wood-panelled refuge in a leafy Tokyo suburb, painstakingly bringing his creations to life. For his latest film, the director reportedly obsessed for months over the colour and texture of the sea waves that wash Ponyo ashore, where she is found by a five-year-old boy.

But once the creative process is complete, he has little interest in what happens, moans Toshio Suzuki, Ponyo's producer and Miyazaki's long-time collaborator. 'He gets engrossed in each movie, then when they're finished he just forgets them and moves on,' Suzuki says.

Suzuki says the director has 'absolutely no sentimentality' for the finished product. 'It doesn't matter how hard he works or how wonderful the movie is. He doesn't even like talking about them afterwards. My job is to clean up his mess. To be honest, he's a pain! But life [here] is always interesting.'

Having experimented with digital and CG technology on Howl's Moving Castle, Miyazaki has gone back to basics for Ponyo, which is made up of a stunning 170,000 individual hand-painted frames.

He says he has seen none of the landmark digital animations of the past two decades, including Toy Story and Pixar Studio's current smash Wall-E. 'I can't stand modern movies,' he says, wincing. 'The images are too weird and eccentric for me.'

Miyazaki shuns television and most modern media, instead reading books or travelling. It is no surprise to find the multimillionaire director's car, parked outside the studio, is an antique Citroen 2CV, an icon of minimalist, unfussy driving. Ghibli's creative engine house is a reflection of its founder's preoccupation with authenticity and distrust of popular culture.

New talent (the studio has just added another 150 animators to its 270 full-time staff) is tested in a sort of animation boot camp, where the use of mobile phones, blogs, iPods and other electronic devices is forbidden. 'Young people are surrounded by virtual things,' he laments. 'They lack real experience of life and lose their imaginations. Animators can only draw from their own experiences of pain and shock and emotions.'

Ponyo, he says, is partly about living without technology. 'Most people depend on the internet and mobile phones to survive, but what happens when they stop working? I wanted to create a mother and child who wouldn't be defeated by life without them.' In a world groaning with increasingly sophisticated movie-making technology, Ghibli's brand of old-fashioned craft looks as vulnerable as a vintage Rolls-Royce on a highway of speeding cars.

Miyazaki compares what he does to old clog makers in downtown Tokyo, now almost extinct, but much prized by aficionados. Miyazaki understands that his style could become obsolete, claims Ghibli's president, Koji Hoshino, but he doesn't care. 'If the audience disappears, that's the end of his dialogue with them,' he says.

'He's not afraid of it. He's fully aware that this is an old-style operation and that's why he decided to do a totally hand-drawn animation with Ponyo.'

As both Hoshino and Suzuki admit, however, Miyazaki's uncompromising approach is expensive. 'We've been doing this for 20 years and each movie costs more than the last,' Suzuki says. Although the director's son, Goro, has also recently made his first film, Tales from Earthsea, the studio is still overwhelmingly dependant on the sparse output of its founder. One flop, unlikely as that is, could devastate the small company.

Enter Hoshino, who was poached from the rival Disney empire, where he worked for 15 years. But Ghibli's new boss denies his arrival signals an attempt to recast Miyazaki's Roller as a sleek American sports car. 'Miyazaki worked in the US in the early 1980s and came back saying, 'Forget it, I'm not going to work like that',' says Hoshino. 'But what Disney is good at is exploiting every bit of commercial opportunity. [Ghibli] has done almost nothing in merchandising outside Japan, so we'll be looking at that, along with foreign distribution.'

Hoshino says a recent partnership with long-time Steven Spielberg collaborators, producers Kathleen Kennedy and Frank Marshall, is an example of the 'much more aggressive and open-minded' tack the studio needs to take. 'I don't shut the door on digital technology either,' Hoshino says. 'Just because Ponyo was 100 per cent drawn doesn't mean we're stuck with that approach. My job is to come up with the best approach to make the most of Ghibli and try to come up with those untapped opportunities.'

Where does this leave the studio's maestro? It's hard to resist the image of a very Miyazaki-like wilful child, struggling to remain unspoiled as the grubby workings of the real world encroach. It's a theme explored in Ponyo, whose rage and rebellion against the world result in a devastating storm. 'Ponyo's rebellion is dangerous, but that's part of life,' Miyazaki says.

'Humans have both the urge to create and destroy.'

Ponyo on the Cliff by the Sea is screening now