JUST 20 seconds into the chat with the son of showbiz luminescents Joan Collins and Anthony Newley, it’s already time to call him out. Alexander Newley has gone all lovely and gushing about his early life in Hollywood, suggesting it was one long series of rides on Steve McQueen’s handlebars, of playing pool with James Caan and watching the likes of Paul Newman and Billy Wilder soak up the poolside sun. “It was fun,” says the artist-turned-writer, in upbeat tone as he talks of the second half of the sixties. “My parents were both big performers, big personalities.”

Whoah, there, Alexander. Fun? In your autobiography (and nicely written it is too) you mentioned you almost drowned during one of those star-soaked pool parties. There was your mother – “weaving, diaphanous in floating colours, taking the temperature of every huddled conversation” – but neither she nor your father noticed your two-year-old self had flipped over in the splash for the longest time. It took your mother’s scream and the party to freeze before your father also saw what had happened and dive in to the rescue.

“You’re right,” says Newley, projecting a little laugh from his studio in northwest London. “There are some downbeats in the piece. But I think any child would have had those in his life. Mine may have been just a tad more amplified because it seemed like everything then was so much more intense; the houses, the places, the people, all so heightened.”

Alexander Newley, nicknamed Sacha when he was a young boy, was born in 1965 when his parents were both arm-wrestling for work in Hollywood. It really wasn’t a great time for him to decide to become their son. Joan Collins was having sporadic success, landing guest shows such as Star Trek and small film roles, her melodramatic performances often a little large for the decade. (Her style would later re-emerge in the Dynasty era.) Meanwhile, Anthony Newley had been a major West End theatre star and a successful songwriter but his full-blown characters didn’t really lend themselves to film at all.

Collins and Newley were also very different creatures. She loved the party circuit, a woman high on life and people and attention while Newley was more often insular and high on chemicals. They both craved fame, yet while Collins would work pretty much anywhere, Newley believed himself a showbiz – and a sexual – adventurer. While working in Vegas for the Mob, women were dropped off to him the way other men ordered a takeaway. His appetite for women and E-Type Jags was insatiable.

In 1969, Newley made his autobiographical film Can Heironymus Merkin Ever Forget Mercy Humppe And Find True Happiness? “It was a balls-out confession in which he rakes over his entire life, recasting it as a grail quest for the perfect piece of ass,” says his son. It was to signal the end of his parents’ marriage. Collins, who had dumped Robert Wagner to take up with the mercurial, often brilliant Newley, realised she could never compete with the streams of very young hopefuls auditioning for the job of her husband’s lover. (She later maintained her ex-husband’s partners were 17 and upwards). The chances of Newley and Collins going the distance were non-existent.

Meantime, Alexander and his older sister Tara were looked after, for the most part, by a nanny. They f*** you up, your mum and dad, don’t they Alexander? “Yes, they did,” says the talented portrait artist whose work is heavily displayed in the book. And he tells one story of how he was being “supervised” by the nanny but had climbed up a tree. His mother called out to ask where little Sacha was, and the nanny said she was keeping an eye on him. She was. But he was still up the tree, and his mother simply accepted that. “I know,” he says, anticipating the question. “My mother didn’t always get it right. But the idea of doing the book engendered lots of conversations. It was cathartic to write it all down. More than anything you give order to your past. It’s also a way of leaving it behind. But it’s an ongoing process.”

Alexander Newley has had a lot to process. With a highly-sexed father and a sex-goddess mother he grew up surrounded by beautiful women such as Natalie Wood and Dyan Cannon. He watched Hollywood cavort. But did the experience leave him, well, normal? “The sixties were a different time,” he explains, smiling. “Very permissive. Very joyous. And people began to look great with fantastic clothes and drugs came in. My father was at the epicentre of all that. My mother was an object of great desire, so I was surrounded by beautiful people and I guess I absorbed that.”

The world was beautiful but no-one was behaving beautifully. Newley’s father, a songwriter who came up with over 40 hits including Goldfinger and Candy Man (he later influenced David Bowie) was, in fact, full of self-loathing. “I think he was an artist first and an entertainer second,” his son explains. “And in the seventies, he was more an artist. Nowadays, more people want to know about him then.”

In 1969, the marriage over, Joan Collins moved back to London with her children to boost her career. Young Sacha was wrecked by the arrangement. “The world wasn’t so small in those days. You didn’t have Skype. But when I (later) saw my dad he had amazing capacity to make up for the absences and fill them to overflowing.” He adds: “I still feel so close to him. His presence was so massive. He was one of those people who, like Sammy Davis, could walk into a room and change the voltage. It’s charisma. But as a kid you feel it.”

Yet, while Collins had had enough of her husband’s flings with (much) younger girls, she never gave up on him. The book includes a letter from Collins to Newley. It’s poignant and touching, reflecting the sadness of their marriage break-up. You don’t have to read too hard between the lines to know she wanted to get back with the often abominable showman. However, her son was well aware this wasn’t likely to happen, given his father’s appetites – and the fact his mother wouldn’t be on her own for too long. Collins’s Achilles’ heel was she needed a man in her life at all times and soon segued into a relationship with record producer Ron Kass.

The children weren’t at the wedding, however, which was emblematic of the separation Sacha and Tara were kept at. Yet, they desperately needed their mother, the actress who would often work on location or simply need to live her own life. They loved her, but described her as a “narcissist” who “abandoned” them. “I just wanted mummy to love me,” said the young voice of Sacha speaking in one of several tracts in the book. “She nourished me in a way a muse nourishes; at a distance.”

While Collins was filming at Hammer, the children were left in the grip, literally, of an enormous, twenty-something nanny called Fat Sue. The book claims Fat Sue would wrestling with young Sacha and getting him to massage her. Does this suggest sexual intent? “There was a lot of S&M,” he acknowledges. “She wouldn’t just sit on me, but sit and grind me into the carpet. Yet I adored her. It was a powerful relationship.”

Did the experience see him sign up immediately for therapy? “I think that my childhood did prepare me for becoming an artist. As you move through your projects you encounter strange forces and intuitions. I’m not squeamish about strangeness. I don’t regret any of it, oddly.”

Alexander Newley chooses to play it down now but the early years living with his mother were often an ordeal. Not surprisingly, he didn’t grow up the average little boy. He was unhappy, would stutter and refused to speak to the psychiatrist his mother took him to see. After four years in England, Collins and co moved back to Los Angeles, and the boy commuted between his parents in a range of different homes. That geographical shift alone must have thrown his head into confusion; one minute he’s living in a quaint Highgate village, the next he’s in Los Angeles. What a trauma for a wee boy? “The analogy I use is my life was full of jump cuts,” he says, grinning. “And it’s true. It’s been like a movie. I became interested in cinema because my life was so like it.”

The young boy would live in large houses and meet Elvis or Rod or Ringo but felt neglected, that he and Tara were “an experiment that failed”.

Newley won’t speak about his current relationship, although it’s likely he’s in one; so much of his life seems to be about a quest for love. “I fell for all my sister’s friends. I’ve always fallen hard,” he admits. But before Collins made it back to the big time with Dynasty, she remained distant. “My mother stalked the house in a self-righteous temper,” he recalls of the return to LA. “Cooking for her kids, doing the school run and entertaining them just wasn’t in Joan Collins’s mission statement.”

There are dismissive notes about his mother throughout the book; he seems to have a coldness towards her, unlike his father, but paradoxically, what strikes as odd is the detail and colour and love he also attaches to his mother. He describes her in ways sons don’t often describe their mum. “Alpha jezebel” and “firebrand”, he writes. And then spends a page describing her put on makeup. It’s almost the mark of a gay man, which he is not. “I would say that young boys do notice that,” he counters. “They don’t hold the information into adulthood, but where artists differ is that the childhood self never really checks out. I have a direct line to the deceptions of the kid in the book, which is why I gave him a voice.”

Aged 11, Alexander walked away from his mother’s perfectly made-up face and took himself off to live with his father. “She had abandoned me to Sue and now I was prepared to abandon her back.” Anthony Newley was performing in cabaret in Las Vegas for much of the time. This meant his son could meet the likes of Elvis (“Black hair dye ran down his pasty white face – he looked all played out – and pissed off”) and receive a white mountain bike from Evel Knievel, which he was much happier about. But the little boy would have been much happier to have his dad at home. Meantime, Collins decided to move back to London to arrest a career and a marriage on the slide. The career would be reprised with soft porn films The Stud and The Bitch, but the marriage hit the skids.

Alexander Newley lived in Los Angeles with his dad for three years, but of course life was never uncomplicated. He didn’t take to his dad’s new air hostess wife and decided he’d come back to England. But not to live with his mother. “I wanted to go some place new,” he maintains. “A place without parents.” Encouraged by Fat Sue, who had come back on the scene briefly, Newley attended boarding school in the Midlands, which is where the book ends.

In spite, or perhaps because of the circumstances of his life, Alexander Newley seems a happy sort. He’ll reflect on how his parents behaved, but doesn’t seem to harbour anger. He says he blames them for their solipsistic behaviour, their inability to put their children before their life-sucking careers, as if this “ogre called showbiz” is somehow not part of their normal character. “I don’t have regrets,” he says of his life so far. “And I have the unique experience of growing up the son of these two amazing creative personalities, at an amazing time of the sixties going into the seventies.”

Anthony Newley died in 1999, aged 67. “My dad is my touchstone,” he says. “He gave my world continuity.” In spite of the frustration/anger/disappointment he felt with his parents, he continues to declare love for both. Joan Collins, he says, is happy with the book, overall. She’s certainly been big enough to support his paintings, particularly his portrait of her, which is certainly revealing. “She hung it in the drawing room and to her credit it’s not for the faint-hearted,” he says, grinning. Indeed, Michael Caine described it as a picture of Doreen Gray. “She’s a trouper,” Newley says of his mother. “And she’s adorable. She’s very strong and with this worldly persona but she has this vulnerability the public don’t see. And I love her.”

Yes, yes, it’s great you’re not spending fortunes lying on shrink’s couches, Alexander. You seem a level-headed, fairly balanced, talented man. But don’t you ever wish your dad were an electrician and your mum a home help?

“No,” he says, laughing. “I think one of the points of the book is owning the history. You have to take possession of it. There are no victims. And I’m more than happy my parents were both were visiting comets.”

Alexander Newley: Unaccompanied Minor, The Tramway Glasgow, March 25, 3pm