I can’t remember where I was in 1971 when I first read Jann S Wenner’s brilliant interviews in Rolling Stone magazine with John Lennon. (They later came out as a book, which is still in print, and are probably the best interviews John ever gave.) I do remember a bit of jawdropping admiration and, yes, jealousy that Wenner had managed to get so much out of him. He’d obviously caught John at a good moment, when he was raging against the world in general and the Beatles in particular. He said that their manager Brian Epstein had forced them into suits and that they’d “sold out”. And he attacked Paul: “When Paul was feeling kind, he’d give me a solo.” Most of all, he rubbished himself, saying what a bastard he had been.

I was enjoying all this when Wenner suddenly asked John about my book, The Beatles: the Authorised Biography, first published in 1968. “Well, it was really bullshit,” said John. He went on to explain that had omitted“the orgies and shit that happened on tour” and that I had allowed his aunt to take stuffout. It was the word “bullshit” that jumped out. I’m sure it gave huge pleasure to all theother Beatles hacks at the time but over the years it has largely been forgotten.

I barely remembered how hurt I had been at the time until, several times in the past few weeks, I was asked about that “bullshit” remark. A Polish TV crew, a German presenter and an Australian radio interviewer all dragged it up. Then, blow me, there came a fourth reference, by the charming but deadly Mariella Frostrup on Radio 4’s Open Book. It wasn’t to the word “bullshit” or directly to Wenner’s interview but she did ask why I hadn’t given details of all the groupies. After all these decades.

In 1971, I rang John up in New York shortly after the interview appeared and he just laughed. “You know me, Hunt, I just say anything that comes into me head.” And it is true that he admitted to Wenner that he often doesn’t make sense. “We all say a lot of things that we don’t know what we are talking about. I’m probably doing it now . . .”

I reminded him that it was he who had asked me to make a change in the book. His Aunt Mimi, who had brought him up, had somehow got hold of a manuscript and was maintaining that John had never stolen or sworn or had fights in his childhood – and she didn’t want any of that in the book. So I went to see her in Bournemouth and explained that that was John’s memory and I could not alter it. I took nothing out but calmed her down by adding a sentence at the end of the chapter on his childhood in which I quoted her saying: “John was as happy as the day was long.” The only sentence I did delete was one

John had asked me to remove – a disobliging remark about a man who later became the partner of his mother, Julia (John had called him “Twitchy”). Paul and Ringo had no objections but George did moan a bit, saying he wanted more written about his views on Hinduism and his spiritual beliefs. I refused to add any more, saying it would unbalance the biography.

When the book first came out, it was considered quite daring and revealing, especially in the US, where the New Yorker’s review said it “does not shy away from any mean and gritty little facts”. I had the Beatles using the word “fuck”, most unusual in a popular book at the time, and also included references to their use of LSD and to how Brian Epstein was a “gay bachelor”. While I was writing the book, homosexuality was still against the law but Brian, by this time, was dead and his mother, Queenie, was unaware of the new use of the word “gay”. I felt it was relevant, as it helped explain why Brian, a middle-class publicschool boy who liked Sibelius, was so fascinated by John. (John and Brian had a holiday abroad, just the two of them, during which, according to John, they’d had a one-night stand. I didn’t believe him, assuming he was just exaggerating for effect. I still don’t know whether it was true or not.)

I have to admit, though, that I didn’t mention groupies in the book or make any references to what happened in dressing rooms and hotel bedrooms in the UK and around the world. Should I have done? No one asked me at the time to omit such things. It was my decision. Three of the Beatles were married, happily as far as I could see, while Paul was engaged to Jane Asher. It seemed unfair to embarrass them by going into what had happened while they were touring, which they had now given up. Most people over the age of 25 in the 1960s were aware of what happened between rock stars and groupies. I felt no need to go into it.

A few years later, John was owning up about the orgies, to Wenner and others, and about what beasts they’d all been – the Beatles and most pop stars of the time and DJs, too – despite their lovely, if cheeky, image.

I recently discovered, for example, the origin of the phrase “I am the egg man”, used by John in the song “I Am the Walrus”. It seems it referred to another well-known singer of the time with whom John had indulged himself at the expense of groupies and whose speciality was giving drugs to young girls, stripping them naked, then breaking eggs over their bodies.

I suppose, looking back, that although I did reveal a few warts, on the whole I subscribed to the carefully cultivated image of the Beatles. Bullshit, or what?

“The Lennon Letters” edited by Hunter Davies is published by Weidenfeld & Nicolson (£25)