SARAH Miles,the actress, is dying. She is in the terrible last stages of arsenic poisoning. Her face is awfully pale and her breathing difficult… She’s filming Dandelion Dead, a television drama based on the true story of a 1920s solicitor who murdered his wife. But her real life is more improbably dramatic and beset with tragedy than fiction.

The star of The Servant and Blow Up to Ryan’s Daughter, Steaming and White Mischief disappears, insisting on having her unflattering make-up removed before she’ll be photographed. But she doesn’t change out of her nightie. She has cascading hair, sad eyes, a pretty face naturally almost devoid of wrinkles and she refuses sharply to divulge her age. Initially, she seems nervy, actressy and incredibly sensitive.

She speaks tantalisingly. Shortly after we start talking, she tells of the fire that raged in her wood-beamed Hampshire home last October. ‘The whole conservatory went up like Manderley. My friends were screaming, panicking. I had no idea of the power of fire, phooooow, extraordinary, so fast,’ she says, in a poetic, delivering-lines kind of voice. (She tends to speak discursively in lengthy paraphrases.) ‘I had bare feet, glass was everywhere and I was chucking bread-bins of water over it.’

Sarah is writing a novel on a computer in her dressing room during film breaks. ‘Filming is so boring,’ she says, wearily. But surely it pays nicely? ‘Alas my piggy bank is almost empty. We had the wrong people looking after us financially. We really messed up.’

Later this month A Right Royal Bastard, her autobiography which charts her life until the age of 18, will be published. (It is embargoed until then and so its contents cannot be divulged.) This is a major feat because Sarah is severely dyslexic. ‘I never took an exam, let alone passed one at school. You grow up with the feeling that you are stupid. There’s an inner pain.’ But 20 years ago, while meditating, she received the ‘joyful message’ that she should write. Since then she’s had paranormal experiences (which she won’t explain) which have allowed her to recall her life very clearly. ‘Alas, I can’t remember back to the womb. A lot of people I’ve met can.’

She says, wistfully, that she had a wonderful childhood. Her father was an affluent engineer (they had servants, which she finds ‘terribly embarrassing’), and she and her three siblings roamed carefree with their animals in Essex. People who have read her book comment, mistakenly in her view, on how sad and unloved she was. ‘They say my mother didn’t love me. But she had every right to be pissed off with me. I was an infuriating, agitated little girl.’

WHENEVER her mother said something important or frightening, a curious thing would happen. ‘A silver screen with black edges would come down in front of my eyes.’ Sarah would be blinded by this vision. ‘It still happens today. Maybe that’s what they mean by blind panic.’

She was frequently hit with a hairbrush, which she found ‘comforting. It allowed me to know my boundaries, to know what was right’. Her voice becomes low. ‘I got whacked after I tried to drown my brother. I was three and pushed him into the pond because I wanted him to go away.’ She failed. ‘He fell in the only part of the pond where there were bullrushes.’ She laughs, a tinkling laugh. ‘I love him dearly now.’

She was also expelled from two boarding schools, including Rodean after a hiccup with Royalty. ‘The Queen Mother was visiting the school. She asked me whether I liked it and I said I hated it.’

Sarah has a son, Tom, 25, by her husband Robert Bolt (the Oscar-winning screenwriter of A Man For All Seasons and Dr Zhivago). In parenting, she tried to compensate for the lacks in her own childhood. ‘I didn’t have cuddles but didn’t feel the loss of them. But maybe I gave Tom too many. I couldn’t wean him off them … I probably did everything wrong. I’m sure I was the most ghastly mother.’

Tom, who was expelled from 10 schools, ended up fighting for his life against heroin addiction. Sarah talks only very reluctantly about this now, for the first time. She is cautious for fear of ‘damaging’ him. Tom has been ‘clean’ for seven years. ‘He’s so strong he’s been able to beat the Devil,’ she says. ‘But less than 10 years ago, he stole everything to get money for heroin. He cleaned us out. He stole every one of my awards and Robert’s Oscars. But he brought back all Robert’s Oscars when he couldn’t sell them because they weren’t real gold. Mine were silver!’ She laughs.

‘During this period, my mother was dying of cancer and Robert, who’d had a stroke, was still unsteady. I was preparing for a ritual where I had to hand Mother over to the next life. I can’t explain it because it’s very personal, but if it’s done gently, it means she gives me some of her spirit when she dies.’ The ritual was interrupted by a phone call for help from Robert.

‘Tom, who was then 16, had come to the house to get money from Robert. I don’t know whether Tom knocked him over. But Robert was on the floor and I thought he was going to have a heart attack. As I went to see Robert, Mother said, ‘Do what they do on telly, call the cops.’ Those were her last words to me before she died.

‘I called the police and when they saw what Tom had done, they put him in jail. When he came out, he became a dispatch rider on heroin. He ended up on the streets, because I threw him out. He was a derelict, sleeping rough. That was tough love, the only way to stop him killing himself, and went on for three years.

‘People used to phone me and say, ‘You’re killing your son.’ I’d say, ‘Thank you’ (politely) and put down the receiver. Finally he nearly snuffed it and we sent him to a rehabilitation clinic in America. You send them to these clinics where you have to pay up front, because they run. You’re paying thousands of pounds each time – and they leg it. We hadn’t got any money left. This time he didn’t run, and he cleaned up.’

LAST year, in an article in the Daily Mail, Tom blamed his condition on his working parents, many nannies, the loneliness of life in a show-business family and his ‘whacky’ and ‘stormy’ mother who would hug him, then suddenly be emotionally absent. He felt unwanted and his drug-taking was an attempt to deaden this feeling. Sarah, with an edge to her voice, denies this. ‘The Press twisted it. Tom had everything he could possibly want in terms of love and friends. But my divorce was terrible for everyone concerned.’ She doesn’t blame herself for his addiction. ‘It’s genetic. There’s a lot of alcoholism on my husband’s side of the family. His daughter from his first marriage died of it. (She commited suicide.) And Robert is a workaholic, foodaholic and drinkaholic.’

She also doesn’t feel guilty because she views the problem in cosmic terms. ‘It’s all karma. Tom and I have an awful lot to work out in this life and we haven’t yet got to the really good part.’ Now, happily, Tom sells watches in markets and is working with Sarah on a musical called Boy, about families and drugs. She’s writing the lyrics and Tom the music.

We talk then about her marriage. In 1967, Sarah married Robert, a former schoolmaster, who was at the height of his Lawrence of Arabia fame. Curiously, Sarah resolved on matrimony after she tumbled down the stairs. ‘Robert was typing in the sitting room and I fell down harshly, bang, and twisted my ankle. His typewriter never changed rhythm and I thought, ‘This is the man I’m going to marry.’ Until then I’d been suffocated by men.’ She was attracted to his implacable self-discipline and dedication to work. But they split up in 1973 after the scandal of David Whiting, her business manager who became obsessed with Sarah and was found dead. Sarah, who’d been filming, returned from a night out to find his body in her Arizona hotel room. Mysteriously, a verdict of a drug overdose was reached, although the inquest revealed he’d taken only two Mandrax.

Sarah had been savagely beaten by him on the night he died and reportedly had evidence of foul play. ‘I’m not prepared to talk about that,’ she says now, ‘I don’t want to go to jail.’ Because people might suspect her to be guilty? ‘Oh please! I only tried to keep the man alive. (He had threatened suicide before.) No, I don’t want to get myself into the papers again by the knowledge that has come about. I can’t ever impart it because I can’t prove it.’

At the time, she claimed the intense publicity ruined her marriage and she practically disappeared to Hollywood for seven years. Is that really what went wrong first time round? ‘We both had huge lessons to learn,’ she replies, simply. ‘Lessons about becoming whole in a spiritual way.’ She divorced Robert in 1976, but remained good friends. He then asked her to remarry him in 1979, the day before his bypass operation and stroke. But instead, he married someone else – Ann Zane, the former Marchioness of Queensbury – although it was short-lived. He was also a vegetable for two years, paralysed down one side and unable to speak.

Their relationship changed after his stroke. ‘Robert was a great raconteur and suddenly he was face to face with the wall, couldn’t speak or move and was told he was going to die. We all thought he was going to die.’ (Sadly, he still talks with difficulty.) What was that like for her? ‘Rather beautiful to see him just lying there accepting everything, and obviously horrific. We didn’t know whether he was all right in the head and he couldn’t tell us. It’s taught me patience. Now it’s a joy to be in service. That’s where true contentment comes from.’

While caring for Tom in the rehabilitation clinic, she re-established her matrimonial commitment to Robert and they remarried quietly in 1988. ‘It would never have worked the second time if it was purely lust that brought us together,’ says Sarah, who once had a reputation as a scarlet woman. ‘I was in love with his spirit, eloquence and wit.’ Now their relationship works in an old-fashioned way. ‘I wouldn’t ever want to be the powerful one in a relationship. I find that unattractive in a woman. I like my man to be dominant and I always put my husband first. He still makes all the decisions.’

Any interview with Sarah has to include the bananas stuff. About Sarah drinking her urine twice daily to immunise herself against allergies – ‘it tastes like every lavatory you’ve ever smelt’.

About her paranormal experiences and spiritual awakening that turned her from her atheism – ‘That’s between me and my maker. But it had a profound beauty and socked me out the fucking sky.’

And about reincarnation, her readiness for death and the value of silence. She talks about it all enthusiastically.