I last saw John Lennon alive in October 1980. It was after a recording session in New York, for what became his Double Fantasy album. We strolled back to the Dakota apartment building overlooking Central Park, which he had owned since 1973. We stayed up late talking. Yoko had fallen asleep.

At the end of the evening, he walked me to the front door. We exchanged a few words – and that was the last I ever saw of John. I remember telling him I was going to walk back to my hotel, The Plaza. It was 10 or 15 blocks. He just said ‘goodnight’. Obviously he had no inkling of what was about to happen. He was shot dead within a few weeks.

Looking back, I consider myself incredibly lucky to have met John and Yoko. I first became acquainted with the couple in 1971 when I interviewed them for a radio show I was presenting. We hit it off more or less straight away. The friendship grew from there.

John lived a very public life. He did so intentionally. He used his celebrity to advance causes in which he believed. For instance, John and Yoko used their honeymoon as a ‘peace event’. Their perspective was: ‘You sell peace the way you sell toothpaste’.

By the time of his assassination I considered we were good friends. I was actually the one who picked John up from the airport in Los Angeles at the beginning of his so-called ‘lost weekend’ in 1973.

It was an aspect of John’s life that provoked a lot of curiosity. He and Yoko had reached some ‘imbalance’ in their relationship, shall we say. She thought it would be a good for John to spend time away from her and from New York.

She suggested he relocate temporarily to Los Angeles, which he did. He was looking forward to his new-found freedom. I remember him asking what life in LA was like. While I don’t think he planned it, he ended up spending a year and a half out here. It was John who coined the phrase ‘lost weekend’ and while I think he had some fun and some laughs, before long his only real desire was to get back to New York and to Yoko. Ultimately, John did not have a happy time in LA.

That isn’t to say he was miserable constantly. He made some very interesting music through that period. He also got to hang with people he really liked – in particular Harry Nilsson. He would also see the other Beatles, if they were passing through. His acquaintances from that period included Keith Moon and Elton John. On several occasions he and I went out with Mick Jagger. John was certainly enjoying himself on those evenings.

Through it all, though, he never stopped missing Yoko. The separation was bittersweet I’m sure. He got to do things that you wouldn’t be able to do at home in a married situation. But he missed the very special connection he had with her. There were very few things that could substitute for it.

What was John’s relationship with Paul like? Well, like any lengthy friendship it had its ups and downs. They would occasionally bicker. John said to me, “it’s kind of like an old married couple – they have known each other forever they are going to have their disagreements and disputes.”

Which they surely did. However, by the end of John’s life, whatever issues he and Paul had gone through, had been resolved. I asked him on a TV interview once “would The Beatles ever get back together?” And he told me: “The wounds have all been healed, the only issue is whether or not we play music together.” People may have thought that Paul and Yoko had a difficult relationship. Tensions spilled over a little into their post-Beatles years. But by the time John left us, Yoko has a very good relationship with Paul.

People may have wondered who wrote what in the Lennon and McCartney partnership. If you look back at the Playboy magazine December 1980 issue, there is a lengthy interview where John, almost song-by-song, sets the record straight as to who composed what, to the best of his recollections.

Many Beatles classics were written by John or by Paul solely. But when Paul sings ‘Give Peace A Chance’, the Lennon song, I think it’s simply wonderful. McCartney is one of the greatest artists of our time.

Returning to the ‘Lost Weekend’ for a moment, it must be borne in mind that the idea of living as a single man held a certain fascination for John. You’ve got to remember that he had never really been a bachelor. He was very young when he started seeing Cynthia, his first wife. She became pregnant soon after the relationship began. Back in those days, when that happened, the man would do the right thing and get married.

He would try to make the best of the relationship – but it wasn’t to be. Then, he went straight from his first marriage into his relationship and subsequent marriage to Yoko. So he never knew what it was to live a ‘bachelor’ life.

Now, as people may know, during that time he had a relationship with May Pang, his and Yoko’s assistant in New York. Whenever the subject comes up, I want to be sensitive with respect to her. I don’t think she likes me very much. From time to time she has passed unflattering remarks about me.

May has written a book and given many interviews describing the meaningfulness of her relationship with John. Who am I to dispute her feelings towards him?

All I would add is that, from what I saw, there was only one woman that John ever loved completely and that was Yoko. I have no wish to diminish May’s perception.

That’s just my take on it. And, of course, as we know, he would return to New York, reconnect with Yoko. And they would have a son together.

John described what would turn out to be his final years of marriage and fatherhood as the most joyous of his life – those are his words not mine. Never once, during that period of 1976 to 1977, did he give an interview saying he wanted to go back to LA. Because he had no wish to.

John didn’t fear getting older. He imagined himself ending up on a little cottage on an island off the coast of Ireland. John always had a long range view and that was what he wanted to do.

You can see his love of Irishness in his decision to christen his son Sean. He specifically spelt ‘Sean’ in the traditional Irish way. He was very aware of his roots. John, in fact, had an enormous regard for Ireland and Irish people. It was part of the blood that fl owed through his veins.

He talked about The Troubles, wrote songs about them, was passionately aware of the political situation in Ireland in the ’70s. He took a great interest, and felt a tremendous sadness about what was happening. You can hear those feelings in the songs of the period.

He wasn’t a political expert by any means. However, he had a very deep grasp of what was happening in Ireland. As did many in America at that time. They were very much aware of the violence in the North and felt a lot of empathy about what people were going through.

It is often said that John was a bad father to his first son, Julian, whom he had with Cynthia. I don’t like the idea of pointing fingers at others in terms of their family relationships. Nobody is perfect. We all make mistakes.

John used to say that Julian was born at the height of Beatlemania. Given the choice between being at home with Cynthia and Julian or going on the Ed Sullivan Show and touring the world as a Beatle, he elected to be a Beatle.

During the years that followed, he didn’t spend much time with Julian. They saw little of one another until towards the end of his life, when they started rebuilding bridges that had kept them apart for so long. Funnily, though, I remember the day John came to my house to introduce me to young Julian, who had come to LA for a visit. He seemed very proud of his son, proud to have been able to introduce us.

One thing is for sure. When Sean was born in 1975 he was determined not to repeat the mistakes he had made with Julian. He was determined to be a full-time, participatory father. He was true to that promise too. He had more of a hand in raising his child than any father I’ve ever seen.

He was clearly making up for previous mistakes. Should he be criticized for the demonstrable love and attention that he lavished on Sean? No. People have criticized him for not being a particularly pleasant dad first time round. I think that is a personal matter for Julian and is for him to address, not others. It has been suggested that Julian did not receive was what due in terms of his inheritance. Certainly, he went through a period where he was angry and disappointed at his treatment. He spoke out about it. But that is now in the past. Julian is well taken care of, those disputes are history. I say this with absolute certainty because he was my neighbour for a time.

Recently, I have only heard him say kind things about his father. I do sometimes wonder how the relationship between Julian and his father might have developed had John lived.

I am not trying to sanctify John. He could be a mean drunk. John just couldn’t drink more than a single glass of something – it was that simple. But he drank anyway. His favourite concoction was called ‘Brandy Alexander’, a mixture of brandy and cream or milk. He liked his beverages chilled.

Harry Nilsson drank brandy constantly. Harry could outdrink anybody I knew in the brandy department. John would have a ‘brandy alex’ or maybe a whiskey sour. Now, if it was only the one he would become even funnier than he usually was – a little looser. He could be delightful when he was at ease. After the second you would see a mood change come over him. After the third you didn’t want to be around John.

He stopped drinking eventually. After he returned to Yoko in 1975 I never saw a drop pass his lips. He was much better without alcohol. Los Angeles was different: he drank quite a lot out there. When he was recording with Phil Spector, you saw a lot of booze in the studio. That was not a happy time for John. He was one of those people who become unhappy if they drink to excess.

Even sober, John had an edge and could be verbally aggressive. So he wasn’t a saint by any means. I loved John but never worshipped him. I didn’t see him as a ‘Beatle’. I saw him as John my friend. That’s how I related to him. We would disagree.

He was opinionated and passionate. That’s one of the reasons we got on so well. John always said what he believed. He wasn’t afraid to speak out. Listen to his records, read his letters. He was a very opinionated man.

Compromise was really not in his vocabulary. If he was after a couple of drinks and we differed over something, he would become angry – and aggressive if he’d had three or four. Now it was never to the stage where he would pick up a baseball hat and hit you over the head. But that anger was part of who he was.

John believed he was followed by the FBI, as it turns out with good reason. It is a matter of historical record that, through the early ‘70s, various intelligence organisations did, in fact, monitor his conversations. For want of a better phrase, they regarded him as a ‘rabble rouser’. He was looked up to by many young people and was openly against the Vietnam war.

Because he didn’t have a green card, the authorities tried, by every means possible, to deport him. He spent hundreds of thousands fighting them in court and eventually received legal permission to live in America.

In terms of understanding John, you have to remember that his mother was killed when he was 15, run over by an off -duty policeman. So, John only got to spend 15 years of his life with his mam.

The nature of his recollections were not as full as those who have spent a lifetime with their mother. He talked about her to me, quite a bit in fact. As people know, he wrote songs that featured imagery of her.

Her passing had a great impact on John. It has been well-documented that, when John was born, his father, a merchant seaman, abandoned the family. So when his mother was taken, he was completely alone. In a way, he felt he had been abandoned twice.

And remember, he was still a teenager. Did that make him the musician he soon became? Well, history will show that soon after his mother’s passing, he picked up his guitar, started making music, formed a band. You could argue he may have found a way “out”, as it were, through the music.

Yes, of course, he was being raised by his auntie Mimi. But being without parents at 15 or 16, you have to rely upon other avenues of expression. He chose to do that through music.

People have commented on the fact that John referred to Yoko as ‘mother’. Should we read anything into it? It always struck me as a term of affection and felt completely natural. When I was with them I would say, ‘Should we go to this place or that place for dinner?’ He would reply, ‘Oh it makes no difference to me, just go ask mother’. It was what I’d call a nickname or a loving expression.

John was not a religious man, though he wrote a song on the subject. It’s called ‘God’. If you listen to the lyrics, his point of view is quite clear. I had a different perspective and we argued passionately. John believed each of us is in control of our own destiny.

Which he was. Until his destiny was taken out of his hands…

Elliot Mintz was in conservation with James O'Brien