Oscar is rolling his eyes and calmly contemplating his meeting with the Prince of Wales the next day. 'It's going to be a great strain not to insult him. I'm going to call him 'Your Highness', but only if he calls me by my real name, which is 'Your Lowness'.'

Oscar can afford to be frank. Thanks to the people who have turned up to film at his home on Sesame Street, New York, every few days for the last 25 years, he's now adored by millions across the planet, though he finds the attention a bit of a drag.

Miserable old thing.

But then that's the point. Oscar is a real grouch. Oscar (he's relaxed about people using his first name) is in London to open a children's exhibition at the Museum of the Moving Image on the South Bank.

It's his first visit to Great Britain. Impressions could be better. 'It's a little too merry over here. Grouches don't like that. People are so polite, they say 'How do you do?' and 'Have a nice day'.' But didn't that come from the US? 'Well, we try to export our worst.'

We met for tea in the Hellenic Suite at Brown's Hotel on Albemarle Street. Yes, the Brown's Hotel. Antique furniture, white linen tablecloths, sumptuous wool carpets, all china and silver service. Not his natural habitat, he admits. 'I was hoping for a nice, dark dustbin down a mews and I wind up here.'

Oscar's big on muck. 'I don't think I've ever had a bath. I never comb my hair - I tried it once, it nearly killed me. I used to be orange by the way, the green's all mould.' What attracted him most to Grungetta, his girlfriend of 17 years was 'her well-matted fur'. She was wearing only a ribbon when they met.

He slams down his china cup. 'Who put sugar in this tea?' He reaches for an egg sandwich and chews (mouth open). But he can't seem to swallow. What a mess.

The prospect of a hotel bed the night before disgusted him so much that a bin was plucked from the street. 'It was pretty nice. I shared it with a rat. I liked his company.'

Dustbins are a testy business with the Grouch right now. Customs seized his regular travelling trash can. 'I prefer trash. I avoid garbage - it slips through your fingers'. Apparently it was not accompanied by the appropriate paperwork. A bit rich, he says, given that it was HM's finest who mislaid the paperwork in the first place.

Meeting Oscar face to face is disconcerting. The intense stare from his deep black eyes never wavers. And when he speaks, his voice seems to drift in from another part of the room. He also scowls a lot, particularly when reminded of the celebrities who regularly stroll down Sesame Street. 'Jeremy Irons came once and he bugged me. He sang. He danced. He was totally charming. I hated him.' Ditto Robin Williams - 'very humorous, very funny, couldn't stand him' - and Hillary Clinton 'very charming, very intelligent, didn't like her either.'

Oscar loves to hate. He'll love Prince Charles.

Oscar the Grouch was born in the Bronx 43 years ago. 'I've always been 43. I figure if you like an age, then stick with it. I was lucky. My mother was the dearest grouch. She always made my oatmeal the way I like it - cold and lumpy.

'My parents taught me never give a sucker a clean break, try not to be nice and if you don't want to be a murderer, then do not mix with people who should be killed. That's not a line you'll hear much down Sesame Street.'

Ah yes, Sesame Street. That haven of tolerance and learning. 'There's no place like it. I like it because there are so many annoying people.' For instance? 'Osvaldo the Grouch, a cousin from Puerto Rico. Cookie - he's a monster, of course. Once he ate all my Aretha Franklin records.' And then there's Big Bird, 'the overgrown bag of giblets.'

Ask him what he likes, and his manner softens. 'I like to see seven-month-old babies eating alone in restaurants, quietly enjoying gazpacho.'

(Photograph omitted)