The news from America is worryingly conflicting. According to some members of Muhammad Ali's warring family, including his estranged brother Rahman and son Muhammad junior, he is at death's door after suffering from Parkinson's for almost three decades now.

Others, among them his fourth wife Lonnie and daughters Maryum and Hana, insist he continues to live "a full and beautiful life" at his Arizona home.

The truth probably lies somewhere between the two. There does seem to be an element of scaremongering about the inevitable demise of the greatest sports figure of all time but when the 72-year-old former world heavyweight champion finally passes away it will be one of the saddest blows boxing has ever suffered.

As the British promoter Frank Warren says, "No-one in sport has ever been more universally loved."

Like Warren, my own sources tell me Ali's condition is now more serious than it has ever been and I pray the man who so revolutionised boxing remains well enough to celebrate the 40th anniversary of the most memorable fight in the annals of boxing - his Rumble in the Jungle with George Forman - at the end of the month.

News of Ali's deterioration coincidentally comes at a time when two of his former same-generation opponents are both hospitalised. Britain's Joe Bugner, 64 is recovering from a heart attack in Queensland, Australia, where he now lives, and 61-year-old Leon Spinks, the former Olympic light-heavyweight champion who sensationally if briefly, took Ali's world heavyweight title in 1978, has twice undergone emergency stomach surgery in Las Vegas.

The health of Muhammad Ali is increasingly frail, it has been claimed by some members of his family, while others insist he is living a "full and beautiful life"  ©AFP/Getty Images

It was his fiercest old foe, Joe Frazier, who once declared when Ali showed no signs of retiring: "The trouble with him is that he doesn't know how to die."

The irony is that, ailing as he is, Ali has managed to outlive most of the 53 opponents he faced in his 61 fights, not least Smokin' Joe himself.

But the one who does look like outlasting him is the man who took that sensational tumble in the rumble in a jungle clearing outside Kinshasa, Zaire, on October 30, 1974, when Ali astonishingly regained the title at 32.

George Foreman is very much alive and still in there punching - metaphorically speaking -  seven years younger than his nemesis at 65.

The pugilist-turned preacher- he has his own Baptist church -  lives in Houston, Texas, from where he tells us he and Ali are still regularly in touch and that he loves "like a brother" the man who upended his career with that single corkscrewing right hand eighth round punch.

These days it is a friendship conducted largely by telephone. "I am not closer to anyone else in this life than I am to Muhammad Ali," claims Foreman. "We were forged by that fight in Zaire and our lives are indelibly linked by memories and photographs, as young men and old men. We have a love for each other.

"If you catch him early in the morning, and he is in good spirits, he talks. His wife Lonnie or his daughter will put him on the phone. He's interested in what I'm interested in, we talk about our children and our grandchildren, and he'll still crack a joke."

Between them Ali and Foreman have 19 children (Foreman's five sons are all named George).

"Once when we were exchanging pictures of our grandchildren by text I showed him one picture, he sent back two. He wrote 'Hey George, how many grandchildren have you got?' I've got six, I told him. 'Well I've got eight, George. See - I beat you again,' he said. He still wants to be 'The Greatest'."

The 40th anniversary of the Rumble in the Jungle will take place on October 30 - a fight postponed by six weeks because of an injury suffered by George Foreman ©Getty Images

The Rumble in the Jungle remains the most bizarre and the most memorable sporting event lodged in my consciousness. It was an epic happening which you couldn't believe unless you were actually at the ringside enclosed in a magnificent football stadium with upwards 60,000 Zairois screaming "Ali bomaye, Ali bomaye.("Ali kill him, Ali kill him").

So much happened on and around that eventful night they could have written a book about it.  Actually someone did. A guy named Norman Mailer. It was called simply "The Fight".

A huge backdrop image of President Mobutu, who had offered an extraordinary $10 million (£6 million/€8 million) to bring the fight to Kinshasa and put the former Belgian Congo he had renamed Zaire on the map, towered over the crowd.

Mobutu had left little to chance. We were taken on a tour of the stadium which had one blood-stained wall with bullet holes where recent executions had taken place.

We were told Mobutu had also rounded up 40 of Kinshasa's leading criminals before the fight and had then publicly hanged in the main square as a warning that the violent city had to be crime free while the big fight circus was in town. Unsurprisingly it was.

Big George, who had won American hearts by patriotically waving a mini United States flag when receiving his Olympic gold medal in Mexico City in 1968, had developed a sullen, Sonny Liston-like aura as a professional, fuelled by resentment at Ali's resurgent popularity.

He recalls."I remember when I first won the world title [flooring Frazier six times in two rounds in Kingston, Jamaica, in 1973] I didn't want to be called the champion, I wanted to be known as a guy who beat Muhammad Ali.

"The trouble was, nobody could beat him. Even when you did, people said you hadn't really. Nobody would say he had lost. It was his autograph they still wanted. He was the one they wanted to hug and kiss."

The fight, promoted by ex-con Don King and bankrolled by the despotic Mobutu went ahead after a six-week postponement when the brooding Foreman's eye was cut in training by a spar-mate's elbow. Foreman was not allowed to leave the country, though Ali was. "When I went to Africa all I wanted to do was get more money," said Foreman, unbeaten in 34 fights at the time.

"Don King agreed to pay me and Ali so much money [$5 million (£3 million/€4 million) apiece] I didn't care where he got it from. Going to Africa meant they weren't going to snatch income tax from us. But I wasn't happy to leave home at all because as soon as I arrived it was clear they loved Ali because of who he was.They just didn't like me. But I wasn't worried by this.

"In boxing, I had a lot of fear. Fear was good. But, for the first time, in the bout with Ali, I didn't have any fear. I thought, 'This is easy. This is what I've been waiting for'. No fear at all. No nervousness.

"I had this air of superiority about me back then. I was going to be the best heavyweight that ever existed. I just couldn't lose. I didn't know how to. But that night something strange and mysterious happened to me.I just couldn't understand it. The punches I had relied on for so many years would land but do nothing.

"In the clinches he would murmur: 'You ain't hurting George, you ain't hurting.' But I could hear him wheeze as I smashed into at his ribs. Then he'd say, 'That all you got George?' Trouble was, it was! Man, he was so brave, so tough.

"It felt like he threw maybe 150 right leads. I can still feel them. I underestimated one of the greatest fighters of all time. That's all there is to it. I underestimated him. And yet I figured he could hit me with all he want, I'd was always going to knock him out. But those punches started to accumulate. And then wham, I was on the floor."

George Foreman was unbeaten in 34 professional fights before the Rumble in the Jungle but was knocked out by Muhammad Ali, who retained the world heavyweight title at the age of 32 ©Hulton Archive/Getty Images

Foreman had also been sucker-punched by Ali's African rope trick.

Trainer Angelo Dundee was in the ring an hour before the 3am start, apparently loosening them, yet told me later: "Honest, I was actually tightening them. But the heat loosened them again. They were 24 foot ropes and I never wanted Muhammad to lay on them and rope a dope. In fact I whacked his butt whenever he did because I was worried Foreman would hit my kid in the chest and knock him out of the ring. But Muhammad being Muhammad he did his own thing. He always did."

Before the fight Dundee has prophesied that hot favourite Foreman would blow up "like an old bull elephant" and that's precisely what happened.

And then came the rains after Ali's Perfect Storm.

Dawn was breaking over Africa as we drove back to the city through mud roads that had become rivers where young kids splash-danced the Ali shuffle joyously chanting: "Ali bomaye, Ali bomaye".

Foreman had been shuttled away in silence. He now says: "I left there trying to find answers. There had to be more to life than eight, nine ten, out! From all that confidence to devastation in a split second. By the count of 10, my whole life was devastated."

Well not quite. Eventually Foreman was to become world heavyweight champion again at the astonishing age of 45 - the oldest in history - knocking out Michael Moorer, an opponent just over half his age.

The George Foreman Grill has turned the former world heavyweight champion into a multi-millionaire, making him twice as wealthy as his former rival, Muhammad Ali  
©George Forman Grill Company

He also found God - and the George Foreman grill, endorsing a franchise which he sold last year for $137 million (£85 million/€108 million), over twice what Ali is currently believed to be worth.

Now he says he prays every day for ailing Ali. "I pray he pulls through because he truly changed the world. I feel such pride in knowing him because he is a hero to me and everyone.

"He doesn't have to say anything now. The time has come where there is nothing else left to say. He said it all. For me, he's the greatest American that ever lived. I think there should be a Muhammad Ali Day in America, maybe on his birthday.

"Last time we spoke I said, 'Look, I've been thinking things over, Muhammad, and I think I can get you now. I want a rematch.' He just chuckled. It is great that he's still in there fighting."

Alan Hubbard is an award-winning sports columnist for The Independent on Sunday and a former sports editor of The Observer. He has covered a total of 16 Summer and Winter Games, 10 Commonwealth Games, several football World Cups and world title fights from Atlanta to Zaire.