For almost 50 years she kept an astonishing secret, refusing to attack the woman who ruined her life. When Cynthia Lennon died aged 75 from cancer last week, the world believed her marriage to Beatles star John had been destroyed by Yoko Ono.

Yet the truth about John and his relationships with women is infinitely more complex, and vastly more revealing of his real character, than the enduring myth.

I know this because Cynthia told me herself. In a rare and never before published interview, she revealed that her former husband believed the true love of his life was not Yoko Ono, but Alma Cogan, a fading female singing star eight years older than himself.

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Please please me: John Lennon meets Alma Cogan in 1964 on TV pop show Ready Steady Go

Extraordinarily, he believed Alma to be the reincarnation of his mother Julia.

It was Cogan’s death in 1966 that threw him into the arms of Japanese artist Yoko.

‘John thought I didn’t know anything about him and Alma, and I never let on,’ confided Cynthia.

‘Now that I think about it, with all the emotion gone out of it, I can see the attraction. Alma was about eight years older than John and very much the Auntie figure.’

John had a soft spot for older women – possibly linked to the death of his mother when he was just 17.

‘Don’t forget that Yoko was also older than John by about seven years,’ said Cynthia.

‘Like Yoko in so many ways, Alma was a very compelling woman. You couldn’t really say that either of them was beautiful, could you, not in the conventional sense.’

She admitted: ‘When Alma died from ovarian cancer, aged only 34, John was inconsolable.

True love: Cynthia revealed her former husband believed Alma Cogan (pictured with Lennon) was the reincarnation of his mother

‘The woman he’d perhaps earmarked to replace his beloved Aunt Mimi [his mother’s sister, who helped to raise him] in his affections was now lost to him.

‘He met Yoko when he needed to, just a fortnight into his grief. She was this obsessive fan who’d turn up and follow him around.

‘She irritated the life out of John to begin with. But Alma died and something odd happened to John. Things turned. Yoko must have seen her opportunity and seized it. She wore the trousers and would control and dominate John for the rest of his life. Yoko was John’s new Aunt Mimi. She worked out what John needed in a woman, right under my nose, and she reinvented herself.’

Cogan – known as ‘the girl with the laugh in her voice’ – was the highest-paid British woman entertainer of the 1950s. She became a household name with the advent of television. Born Alma Angela Cohen to a Russian-Romanian Jewish family in London’s Whitechapel, she had her first hit, Bell Bottom Blues, in April 1954 – four years before the death of John Lennon’s mother.

Cynthia said: ‘She was this typical East End Jewish glamour girl, with a heart of gold, a beehive and these amazing frocks – not the sort of thing I’d ever have been seen dead in myself. She was a bit passé. Her songs were all 1950s America froth like Dreamboat and Sugartime.

When Alma died aged 34, John was inconsolable

‘When John and I were at Liverpool College of Art, Alma Cogan was a big star. John couldn’t stand her, he used to take the mickey out of her all the time. He’d do this wicked impersonation of her.

‘At the time, I would never in a million years have thought that he could have fallen for a woman so much older than him, whose music he couldn’t bear and who he ridiculed mercilessly. But he couldn’t help himself.’

When The Beatles became famous and shared a bill with Cogan on TV’s Sunday Night At The London Palladium, it was inevitable that they would join the guest list of Cogan’s legendary parties at her opulent flat in Kensington, West London.

‘I never got invited, I was kept under wraps,’ said Cynthia.

Love me do: John and Cynthia in 1966, four years after their marriage

‘John was a famous pop star and it was all about keeping the legions of female fans happy. It wasn’t good for his image to have a wife and baby trailing on his coat-tails. His manager Brian Epstein insisted and I just had to accept it. Everyone who was anyone used to go to those parties: Princess Margaret, Noel Coward, Roger Moore, Audrey Hepburn, Michael Caine, Cary Grant.’

Cynthia told me: ‘I never went,’ although she described the apartment in her memoir, A Twist Of Lennon. It was on Alma’s piano that Paul McCartney composed Yesterday.

Although Cynthia never sought proof of her husband’s affair or confronted him – she was accustomed to his infidelity – there was no doubt in her mind that Alma and John were sleeping together.

She had watched them at recordings and functions and said that it ‘didn’t take Albert Einstein’ to read the body language.

I don't believe he was ever happy - and that kills me

There was, she said, an ‘easy intimacy’ between them. They flirted openly with each other, regardless of who else was in the room. Cynthia described it to me as ‘a woman’s intuition’, a ‘gut feeling’. She ‘just knew as a wife does’. When ‘well-meaning friends’ told Cynthia that John and Alma were booking into hotels using aliases such as ‘Mr and Mrs Winston’ – John’s middle name – and even sporting disguises, Cynthia could not have been less surprised.

Cynthia told me all this when we met in London in 1989, shortly before the opening of her ill-fated restaurant Lennon’s. At the time, I was researching a book – which was never published – and this is why for a quarter of a century our conversation remained confidential. She had divorced twice more since John. But Cynthia had reverted to using the surname Lennon by the time I caught up with her, because it was ‘good for business’.

Cynthia chain-smoked and poured endless wine. ‘It all began with the death of John’s mother,’ she said. Julia was knocked down and killed by an off-duty policeman driving outside Aunt Mimi’s house in July 1958.

‘It was complicated, the way that all happened,’ Cynthia explained. ‘The effect of his mother’s death on John’s psyche was profound and damaging.

Cynthia Lennon died aged 75 earlier this week

‘He was 17 years old and I don’t believe he ever recovered from it. It disrupted his ability to have normal relationships with women.

‘His mother was bohemian, an uninhibited sort, who had given John up as a little boy into the care of her childless elder sister Mimi Smith and her husband George. Julia was estranged from John’s father, Alf, and was living with another man [Bobby Dykins].

‘John went to visit Julia whenever he could. He idolised her. She’d taught him how to play various instruments and got him his first guitar.

‘Mimi brought John up very strictly. Julia was arty and laid- back. John identified with her. He was very much his mother’s son. Although Mimi worshipped him, John was a disappointment. To her, he never fulfilled his potential and wasted his opportunities.

‘Mimi disapproved of us, of course. I’m not sure any girl would ever have been good enough for her John. When John and the boys went to Hamburg, I rented his bedroom at their house, Mendips, from Mimi. I have often thought there was something of the “keep your friends close and your enemies closer” about the arrangement.’

It was inevitable that as their fame grew, the Beatles would cross paths with Cogan. ‘They became part of that same showbusiness world. When I first heard about them, I didn’t care, to be honest. I was deeply in love with John – I have always been in love with John. I have never stopped loving him. Once you have had a child with someone, the bond that you have never leaves you.

‘I realised early on that I was going to have to share my husband with the entire world. But it was the so-called Swinging Sixties. Times were permissive, apparently. Everyone was doing everything with everyone. John would do as he pleased. I had always known that about him.

‘I couldn’t change him, I couldn’t control him. So I accepted him as he was. All that mattered was that he came home to me, and to our son Julian.’

After the tragic death of John’s mother, his relationship with Cynthia intensified. He wrote passionate love letters and could be fiercely jealous, but he never wrote songs for her. Those were reserved for his dead mother, notably the songs Julia and Mother. When John and Cynthia married at Liverpool’s Mount Pleasant Register Office on August 23, 1962, Cynthia was pregnant. Julian was born on April 8 the following year – seven months after the release of the Beatles’ first single Love Me Do, and on the brink of the Beatlemania that consumed the world.

Cynthia was adamant that, had Alma lived, John would never have abandoned his family for her. The affair, Cynthia believed, would have fizzled out and John would have come home with his tail between his legs, ‘as he had always done’.

John Lennon, pictured with his first wife Cynthia Lennon, on a plane in New York in February 1964

When Cogan’s star began to fade, she resorted to recording Beatles songs such as Help.

But tragedy was about to strike. Cogan collapsed during a tour in 1966 and died in hospital on October 26 with ovarian cancer.

Crazed with grief, he confessed to Cynthia, she said, that Alma was a reincarnation of his late mother.

After her death, John found his new ‘Aunt Mimi replacement’ in Yoko Ono.

Former BBC Radio 1 DJ Andy Peebles – who interviewed Lennon just 48 hours before he was shot dead in New York in December 1980 – told me recently that John always addressed and referred to Yoko as ‘mother’.

So did Cynthia really believe that Cogan was John’s true love? ‘We can convince ourselves of almost anything in grief,’ she said quietly.

‘Because she was dead, it was safe for John to convince himself of that. It didn’t threaten anything else. It certainly didn’t threaten us. It couldn’t.

‘As I said, he was complicated. More screwed up than most people ever knew. I wanted more than anything for John to be happy.