Julia was flabbergasted. But what about John – who was 16 in 1956 and eager to spend as much time as possible with his mum and two half-sisters in the so-called “House of Sin”?
“He would have walked out straight away, wouldn’t he?” says Julia. “I can’t put words in his mouth, but he would have left. Mimi had John there under false pretences. She had stolen him from his mother for moralistic reasons, because she was living in a common-law marriage – and then she’s sleeping with a 24-year-old student! All our lives could have been so different.
“I think Mimi was envious of my mother, who was the favourite of my grandfather. She was bubbly, beautiful and talented.”
Julia also describes her musical mother, who taught John how to play the banjo, as being the seed for the birth of The Beatles: “Absolutely! The original Beatles were Julia and John.”
Much of the 1960s, of course, were a blur of Beatlemania, while her world-famous brother marked the 1970s by setting up home in New York, with second wife Yoko Ono.
Keeping in contact wasn’t easy – at one point in the book, Julia describes how she was sent packing from the Apple offices by a receptionist who didn’t believe she was John’s sister.
But she especially treasures a series of phone conversations with John, circa 1975: “They were special times; absolutely lovely. And all our talk was focused on our mother.”
Then, not long after John and Yoko’s son, Sean, was born, in the October of that year, the calls and letters from John stopped. And it seemed impossible to get hold of him: “I think they had waited long and hard for Sean and I think he became the primary carer – and we all know that’s totally engrossing.”
But Julia has her priceless memories – and now the chance to tell it like it was.
“This book has been the most cathartic thing I’ve ever done,” she says. “And now it’s finished and I have credited my mother’s account. I feel I have done my mother justice.”