We’re lunching in Lola’s, a smart restaurant not far from where she lives in some style in North London. There is difficulty from the off. She appears to be allergic to the entire menu. Fortunately, the restaurant rises to the challenge. Can they rustle up an ordinary salad? “Madam,” says the waiter, “for you it will be a very special salad.”

Before each course she downs a macchiato coffee. Yet although she has been up all night with her cold-ridden three-year-old daughter Esme, she fails to look as exhausted as she must feel. Her eyes, a colour-chart match for the Japanese kimono she has thrown on, are the bluest I have ever seen outside of a baby’s face — a coincidence, since Morton’s curved forehead and protruding mouth always make me think of babies anyway. If today she does not look as if she has just been plucked from an incubator, it is because her hair has grown back from the close crops she wore for Spielberg’s Minority Report and for In America, Jim Sheridan’s multi-Kleenex weepy that opens in London on Friday.

Her babyish features do not, however, make her a babe in Hollywood’s eyes, and today she is furious because she claims she has just been turned down, on lookist grounds, for a big new Miramax movie, The Brothers Grimm, by its producers, the brothers Weinstein. “Bob and Harvey Weinstein don’t want me to do it because the tops of my arms are too fat and they’d have to pay me properly,” she says bluntly, referring to her market value as an Oscar nominee.

Did they ask her to slim? “No, they didn’t make me that offer. They just said I was too fat. And Terry Gilliam (the director) was like, ‘What do you mean I can’t cast this woman?’ We did two screen tests and then they said I wasn’t beautiful enough. You go, ‘OK, well beauty’s in the eye of the beholder. Let’s have a vote on it,’ so they asked everyone else and the other actors really wanted me to do it.”

But not Miramax? “Not Harvey and Bob. Well, it’s their money, isn’t it?” (When I ring Miramax later, incidentally, they deny that she failed to get the role because of her weight and point out that, as it is a co-production, many voices contribute to decisions about the film.)

I say I’ve lost the plot on screen beauty. She looks lovely to me – and not a pound overweight, although her “bravery” for showing off her body was a talking point when people saw her nude in Morvern Callar, made shortly after Esme’s birth. (Her shape is even a minor issue in Woody Allen’s Sweet and Lowdown, where her screen lover, Sean Penn, calls her “round – I don’t mean fat”.) “

Oh cheers,” she says, pocketing my compliment. “To me what transcends all of that is something from here.” She points heartwards. “I think that’s destroyed by this Angel Delight fluff, this ready mix of the right teeth, the right lips, the right shape. It’s like Stepford Actresses, isn’t it?”

The temptation is to surmise that Morton takes rejection badly and conclude further that this is because her childhood was full of it. Although the facts of her early years are still occasionally fought over in the press by her relatives — and Morton is beyond correcting every untruth — the bare details are that she was born to parents on a Nottingham council estate. They broke up when her father got the babysitter pregnant. Morton went to live with him and the babysitter, who became his wife. When that did not work out, she was placed in care, in children’s homes and with some 16 foster parents.

“I was on a thing called an Interim Care Order, which meant that my real father legally had the right to come and get me at any point. But he didn’t. So after two years with a family I’d be taken away, even though they’d want to keep me and I’d want to stay and everything was fine . . .”

Such a sad system, I say. “It was bollocks. And that’s why you don’t fit in, because you’re the one with the funny voice or you’re the Bible basher because you go to church . . .”

She once said it was a good training for an actor because she learnt the nuances of so many different families, down to how they held their knives. Yes, she says now, but she didn’t become an actress because she was in care. Morton, it is clear, is as keen to disassociate her talent from her background as a Redgrave might be. Perhaps more so.

She arrived in London ten years ago, armed with nothing but an introduction from her drama club tutor in Nottingham. She had an agent within a week and soon found television work. She was Mandy, the car thief in an episode of Boon, the schoolgirl impregnated by a cult leader in Cracker and then, in 1995, she became quite famous as Tracy Richards, the 15-year-old prostitute in Kay Mellor’s Band of Gold. Morton began giving interviews about her upbringing. The links were duly made between her broken-homed childhood and the runaways she played.

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