Neil “Razor” Ruddock is considering a question about whether he might be able to fit into today’s hyper-athletic football world, with its fitness data and dietary requirements, when he breaks into a characteristic guffaw.

“Come on, today’s football? Could you imagine me on 300 grand a week?” he roars. “I’d have spent 301. I’d have gone off and bought myself an island and lived my life.”

This is not an exact transcript of what he says, incidentally. What he says is punctuated by a liberal splatter of colourful language. And a lot of laughing. But that’s what we have long expected of Razor. The life and soul of every football party, first to the pub, last to leave, he was once nicknamed by Roy Evans, his manager at Liverpool, as the Pied Piper because of the way he led others to mischief. Or at least that’s how he used to be. Before he was obliged to pay the bill for all that excess.

“Truth is, Razor nearly killed me,” he says. “I’m not saying that I didn’t have a good time as Razor. I had a right laugh. But I had to save my own life, really. Stop being that bloke or I’d be dead. Simple as that.”

Driven by the booze and an out-of-control takeaway habit, a couple of years back he had ballooned to nearly 30 stone. None of his clothes fitted. So vast was he, he could walk no more than a few paces before feeling faint.

“We live in a three-storey townhouse and I didn’t go upstairs to the top floor for three years, too much hard work,” he recalls. “If a pub didn’t have a car park I wouldn’t go. One day I went to Chester Races, came out and there’s a 400-yard hill up to the station. I wouldn’t walk it. Got a taxi there. 400 yards. Madness. I’d tell everyone it was my knee. But I knew I’d collapse if I tried. Secretly I was terrified.”

‘Telly saved my life’

Football’s principal hellraiser felt wretched, fat and hopeless. What made him finally act was a bit of reality television. A veteran of the genre – he has appeared on I’m A Celebrity, been locked in the Big Brother house, won Celebrity Masterchef – he was invited to participate in a show called Harry’s Heroes, in which Harry Redknapp took a bunch of renowned ex-pros to play a team of German veterans.

“Telly saved my life,” he says. “Seriously, that made me realise how low I’d got.”

In the programme, he was filmed having a stand-up row with Paul Merson (watch below – video contains bad language), himself a man who has chased down demons of drugs and gambling. Merson told him he needed to sort himself out. Ruddock was having none of it. Their altercation was ugly and serious. Television gold, maybe. But for him, a telling moment.

“Merse was trying to give me advice,” he says. “But it was a bad time, I’d got a hangover, I was feeling low, and I went off on one. At the time I thought I was right. How wrong I was.”

The next morning, in order to prove Merson didn’t know what he was talking about, Ruddock joined training. Immediately he felt faint. He collapsed and was taken to hospital.

“In my head, I was worried about dementia,” he says. “Heading the ball. That was my job. I must have headed 50 balls a day. The specialist said it’s not dementia, it’s your heart. I went: thank f--- for that.”

His heart was racing at 140bpm even when he was resting. He had to have it stopped to readjust its pace. And the reason it was malfunctioning was clear: the abuse his lifestyle had inflicted. In order to sort himself out, he had a gastric band fitted. Within a year he had lost more than 10 stone. His weight, while still above his playing size, has been on a downward trajectory ever since.

“I can eat what I want, but not much. I get full up,” he says. “It’s not changed my taste buds. I still go to the Indian with my mates, order 30 quid’s worth of curry, then eat four pounds’ worth.”

But the sleeve was not the only thing that had to change. He had to re-set his priorities, stop being the Razor of old.

“It’s not difficult,” he says. “In the old days of Razor, boozing came first, family second. Not any more. Now family is first every time. And I love it.”

This transformation in his mentality is at the core of his fascinating new memoir. Called Toxic, it is as searingly honest a sporting re-appraisal as any committed to print. This is the story of a man who sorted out not only the scale of his stomach, but the turmoil in his head.

“I did a book before, a few years ago. I needed a bit of money. Did it in three hours, just silly stories,” he says. “Since then I’ve had to save my life, really. So I wanted to do a proper one.”

In the book, he suggests his decline into what he calls the darkest of dark places began almost 30 years ago, when he was playing for Liverpool.

“I got dropped from the [1996] FA Cup final,” he tells Telegraph Sport as he sits in the office of his publisher. “Playing at Wembley in the FA Cup final, for people of my generation, that was the thing. I’d played the quarter-final, the semi, played the last six games of the season. Then Roy Evans, who I love, pulled me aside the Friday before the game and said: ‘I don’t know how to tell you this.’ I went: ‘no gaffer, please. Not that.’ There were only two subs in those days, I knew that was me out. My dad had bought 50 tickets. I had to ring him and say I’m not playing. I was in tears. I felt I let my dad down. That’s when I started what I call cheating drinking, hiding it. Basically I went on the p---.”

He had always been a drinker, a leading member of the Tuesday Club everywhere he had played, spending his one day off in the pub, making everyone laugh at his pranks. But after his disappointment the drinking was no longer restricted to Tuesday.

“You’d get weighed Friday morning,” he recalls. “I found if I got smashed Thursday night, I’d be that dehydrated, I’d make the weight.”

His descent into the bottle took its toll. His career nose-dived. From Liverpool he went to West Ham, then to Crystal Palace where, on the day of his debut, the club’s kit man couldn’t find him a shirt to fit. When he retired, there was nothing holding him back.

“At first, I thought it was great, retirement. I had a few bob, not doing nothing. But then I thought: where can I get the buzz with the lads? It was pubs. I knew Monday to Sunday which pubs round our way would be busy at lunchtime. That was what I did: my wife would be off with her horses and I’d be at the pub.”

His evenings were hardly alcohol-free either. He found a new source of income from after-dinner speaking (his brilliantly told tales of old-school excess were much in demand), where he would cheerfully drink even more. And eat, hiding the pile-up of takeaway wrappers from his wife. It is not hard to see where it all went wrong: Razor took over.

“It’s not like I’m a split personality. I don’t worry if people call me Razor still. But I know I just can’t be him anymore.”

Intriguingly, Ruddock came to that conclusion without any therapy. Given the ultimatum by how far his physical health had deteriorated, he says he just sorted himself out.

“I lost faith with therapists when I did Big Brother,” he says. “They made a big thing about getting a psychologist to check you out before you went in. Anyway, on the day, we all went in one by one, and I was last on the list. They’re all in there for ages. I was waiting for eight hours. I finally see the geezer and after about five minutes he goes: ‘yeah, you’ll be all right in there.’ I realised, it was the end of the day, he just wanted to go home. This wasn’t therapy, he’d had enough.”

Besides, he adds, his upbringing in football had gifted him resilience.

“I was brought up in a football world where depression didn’t exist. Grow a pair of b------s and get on with it. That’s what your manager would say. I guess that’s what I believed: sort yourself out.”

‘I cook every day’

And that’s what he did: sorted himself out. Now, rather than seeking release in a glass, he prefers to cook, a new skill picked up again on reality television.

“Masterchef got in touch: ‘could I do the Celebrity version?’ I said: ‘I can’t cook.’ They said: ‘right you’re in,’” he cackles, his comic timing enviable. “I just picked it up. It’s about noise.” He stops talking for a moment to deliver a pitch-perfect impression of when you know a steak is ready.

“Now I cook every day. In the morning, I find on the telly a cooking programme, watch it, if I fancy a recipe from it, I’ll go out, get the ingredients and cook it. I done Rick Stein’s salad niçoise yesterday. Got me beans, me tuna, my anchovies. Done it for me and the wife. Lovely.”

Healthy food, no more than a glass of wine a day, and spending time with his family: that is his recipe for transformation. It seems easy.

“It is,” he says. “Mind, it helps if you have the love I have from my wife and kids. And other people. The love and support I got since I lost my way has blown my mind. When I lost my weight, I did a tweet, 4.6 million views it had. That helped me in my recovery. Because I didn’t think anybody would bother about me anymore. The love I got put me in the place I am now.”

Which brings us back to the question: how would the new version of Neil Ruddock fit into modern football? Now clean, healthy and sensible, could he cut it these days?

“Not sure I like modern football,” he says. “I can’t remember when I last watched a game all the way through. It frustrates me, VAR and all that. Listen, I’m not a fan of Arsenal, all them Arsenal fans who think they invented football, it drives me f------ mad. The other day I’m watching them, a VAR decision went against them and I had the hump. That’s me, feeling sorry for Arsenal, that’s how bad modern football is.”

And he is off laughing again. Enjoying life once more.

Toxic by Neil Ruddock is published by Headline