"Would you be free this afternoon? My boyfriend needs a haircut.” For Leslie Cavendish, a 19-year-old Jewish hairdresser, this was the most important question he’d ever been asked. The boyfriend was Paul McCartney.

From 1966 until they disbanded, Cavendish was the Beatles’ hairdresser, trusted to tame the most famous mops in pop music. When I speak to him now, he is 70 years old and promoting his memoir, The Cutting Edge. Cavendish is full of stories.

Born on Cable Street in East London, his family were originally refugees from Poland. An unremarkable childhood — Jewish but light on the Judaism, heavier on the football — Cavendish was bar mitzvahed and then a reluctant member of the Orthodox Yeshurun Synagogue in Edgware. Was the Cavendish family observant, I ask. “No no,” he laughs. “We used to call ourselves ‘twice-a-year Jews’ because we only went to shul on Yom Kippur and Rosh Hashanah.”

Cavendish was one of three Jewish pupils at Chandos School in Stanmore and was made aware of it daily: “We had a bit of a hard time there,” he recollects with stoicism. “I remember very clearly that a kid once grabbed me tightly in a headlock, calling me ‘Jew boy’. The biro he had in his top pocket went right through my lip.”

Other prejudice was less physical. He remembers how being called a “shonker”, a slur mocking his Jewish nose, gave him a sense of otherness more profound than the scar on his lip. A universal love of football healed the wounds between Cavendish and his classmates but as he grew up, the dream of making it as a professional player faded.

It was the lure of girls that drew a teenage Cavendish towards hairdressing in 1962. “My best friend Lawrence Falk worked in a hairdressing salon called Eric’s on Baker Street,” he says. “Lawrence was a very good looking boy and the girls used to love him. I went to his salon and saw the stylists surrounded by all these beautiful women.”

At 15, he applied to be an apprentice at the salon run by Vidal Sassoon in stylish Mayfair. It must have been intimidating. “Well, I’d never heard of him. I thought it was the name of a hairstyle,” he admits. “But I told my aunt Gladys that I was going to an interview for Vidal Sassoon and she replied, ‘That’s strange. We used to go to the same Jewish clubs together in the East End.’”

It was meant to be. Sassoon was another Jewish East Ender who was already making a name for himself with his trademark geometric hairstyles. Cavendish got the job as a junior.

“At 15 years old I was suddenly thrown into it. Shirley Bassey, my mum’s favourite, would come in. And Mia Farrow.”

As did Jane Asher, another cultural icon of the decade, who also happened to be Paul McCartney’s girlfriend. It was after her haircut in 1966 that she asked Cavendish if he would be free to cut her boyfriend’s hair that afternoon.

But the answer was no. Queens Park Rangers were playing Swindon that day; Paul McCartney would have to wait. “I made the appointment for 6pm so I could watch the match,” he admits, laughing to himself. The chutzpah of it all still tickles him.

“Paul was living in a nice Georgian townhouse in St John’s Wood. I walked in past the groupies waiting outside the gate and the first thing I saw on the left was an Aston Martin.”

Was he intimidated? “Yes, I used to love The Beatles. I thought they were fantastic. But Paul made me feel very relaxed. The band had finished touring for the first time in five years so his hair was longer and he was unshaven. He didn’t have to be Paul McCartney. He just wanted it trimmed and left it to me. I tidied it up a little bit.”

After that first encounter, Cavendish became McCartney’s personal hairdresser and soon was tending to all of the band members.

“I never asked them for an autograph for myself or anyone else, as I never wanted to bother them, so gradually I gained their trust. For a London Jewish boy to get involved in all this was a nice situation. I was listening to Beatles music that wasn’t even out yet.”

Even Cavendish’s family could not escape his famous clients. “When I got home one day my grandmother said to me in her thick Russian accent that, ‘a Paul McCartney called for you’ and she’d had a nice little chat with him. I told her he was a member of The Beatles and she replied, ‘oh, the one who needs a haircut’. So I told her, ‘you do know that I cut his hair, right?’”

In 1967, Cavendish’s hippie bubble burst. Working at a salon in Park Lane, he saw on the front page of the Daily Express a map of Israel with thick, black lines pointing towards it from every direction. The Jewish homeland was under attack, and something changed in him.“I felt like the arrows were pointing straight at me,” he remembers.

Did it reawaken a sense of Jewishness in him? “All the shame and anger and feelings of injustice which had burned inside me during my school days were suddenly rekindled.

“I decided to go to Israel as a volunteer. I asked Vidal Sassoon if I could go out there and because he had been to Israel as an IDF fighter in 1948, he said, ‘of course you can’. He shook my hand, wished me luck and looked upon me like a proud father.

“When I told Paul that I was going to Israel, he asked if I was going to fight. I told him I was going to work on the kibbutz.”

Throughout the summer of 1967, Cavendish worked on Kibbutz Mahanaim in Galilee, before returning to work as the Beatles’ hairdresser.

During an interview with Disc Magazine, Cavendish let slip that John Lennon’s hair was less thick than the others’.

“The next thing I knew, Derek Taylor, the band’s PR officer, rang me late at night. ‘Did you tell the press that Lennon’s going bald?’ I picked up the paper and there it was. I panicked.”

Only a fool, or a naive 20 year old, would incur the infamous wrath of John Lennon. “John phoned and I grovelled, crying, ‘I’m so sorry, she’s taken me out of context and I never said that...’”

Lennon stopped him mid-grovel: ‘You don’t need to explain what the press is like. Look what happened to me. I said we were bigger than Jesus and America wanted my head on a plate. But I should ask you, am I going fookin’ bald? Because you’d better come over straight away and stick it together before it all falls out.’ Cavendish survived, just.

He has been married and divorced twice. His current partner, Susan, is also Jewish. “We both respect being Jewish. We’re proud of it. We have Friday night dinner every other week.” They share their time between Marbella and London, where he manages All Aboard’s East Finchley shop.

He last saw Paul McCartney in 2012. “I saw him at the British Film Institute. I took my son with me and he asked if Paul would recognise me. I thought about how many people he would have met in the forty years since we last saw each other. I wasn’t going to go up to him and say, ‘Do you remember me?’

“As I was walking out he saw me and said, ‘Leslie!’ He put his arm around me and we walked out of the theatre arm in arm. I looked at him and said, ‘I told you you’d never lose your hair’.”

The Cutting Edge is published by Alma Books