Less than half a mile from the stadium where he was adored by supporters of Manchester United, Norman Whiteside would shuffle into North Trafford College with his physics homework. The rest of the class was made up of pimply teenagers. He was a grown man who had played in two World Cups and scored in an FA Cup Final, but he still had to recite Archimedes’ principle.

Going back to school to take his GCSEs was, Whiteside says, the most frightening thing he has done; more terrifying even than facing a crimson Sir Alex Ferguson after yet another bender.

But he did it, which is one of the reasons why his forthcoming autobiography is called Determined rather than “Always Look on the Whiteside” or “Belfast Boy”. “I chose Determined because I’ve always been like that, whether it’s becoming a footballer or going back to school,” he said. “I decided not to swear when I was 11 and I haven’t since. I’m like that when I set my mind to something.”

From sharing a bed with two brothers in a terrace house off the Shankill Road in Belfast, Whiteside’s single-mindedness brought him 272 appearances for Manchester United and 38 for Northern Ireland before a battered knee cut his career brutally short at 26. He likes to look back with a laugh rather than regrets and he likes to do so with a drink in his hand. His determination on the day we meet is to break records for Rioja consumption.

The longest of lunches follows an unexpected reunion with Paul McGrath, his former United teammate. Great friends, their stories have been entwined in the public mind since Ferguson turfed them out of Old Trafford in a 24-hour purge of the unruly drinkers. As he summons another bottle of red, Whiteside, now a jowly and jolly 42, is not about to deny that he likes either the taste or the warming glow of alcohol, but he is adamant that injury rather than booze brought about his premature exit from Old Trafford. As his first manager, “Big” Ron Atkinson, might have said, Whiteside can drink for fun. McGrath would drink to oblivion.

“Paul might have a different answer, but I always felt in control,” Whiteside said. “If you’re 18, 19, playing for the best club in the world, getting reasonably well paid, you are entitled to go and have a few beers. I never thought it was harming my football.

“I have admitted my part of it [the drinking culture], but Bryan Robson could and would drink more than me. But he was the best player in the country and he didn’t have a dodgy knee.”

Whiteside had a serious operation even before his record-breaking appearance for Northern Ireland in the 1982 World Cup finals. At 17 years and 41 days, he was nearly six months younger than Pelé had been in 1958. Sharing a plane with the great Brazilian one day, Whiteside took childish delight in mouthing “only the second-youngest” behind Pelé’s back for the entire journey.

He had played only 102 minutes for United before his World Cup debut, making Sven-Göran Eriksson’s choice of Theo Walcott at last year’s World Cup finals seem almost conservative. But while he was youthful in age, the Shankill Skinhead might have been born with stubble.

A heavy tackler as well as a heavy drinker, Whiteside is best loved among hardcore United fans not for his FA Cup-winning curler against Everton in 1985 but for one memorably violent appearance off the bench at Anfield. United were trailing 3-1 but came back to draw 3-3 thanks to Whiteside poleaxing John Barnes with an elbow and catching Steve McMahon somewhere below the neck. “I kicked lumps out of them,” Whiteside recalled, proudly.

The combination of brute force, deft touch and vision on the ball would lead Ferguson to describe Whiteside as “close to the genius category”. But his time was always going to be limited; he was only 21 when a United physiotherapist drove him home after yet another operation and predicted bleakly that “you’ll only have another five years”. The forecast was accurate.

While he gets on well with Ferguson these days - it is hard to imagine Whiteside falling out with anyone - he disputes his former manager’s assertion that his drinking showed a “contempt for his career”. But Ferguson’s word was law and the end came shortly after McGrath and Whiteside made a sozzled appearance on a Granada television show, giggling like naughty schoolboys. “I was driving, so I know I wasn’t off my head,” Whiteside said, but McGrath had downed a skinful for Dutch courage.

Asked if he should have done more to help his old friend, whose battles with alcoholism were painfully recounted in his own autobiography last year, Whiteside’s joviality slips for a second.

“I did help Big Paul,” he said. “When he was banned from driving, I picked his kids up and took them to school. Robbo was banned at the same time [Whiteside would be later] and I ran their families around and then took them to training.

“Listen, I was as shocked as anyone reading Paul’s book. I certainly had a few tears. He had never mentioned half that stuff to me.”

So what did they talk about last week? “We just sat and giggled, talked about how good we were,” Whiteside said. “We were looking at the happy side.”

What relevance has Whiteside’s story today? Well, plenty for the United supporters who roared him out at Wembley in May, when he joined a parade of renowned FA Cup finalists. There would be collective embarrassment on the Stretford End when reminded that only 7,434 turned up for his testimonial in May 1992. The fans did not have the stomach for another match after narrowly missing out on the title to Leeds United, but that was no consolation for Whiteside, who could have done with the money.

Just as football’s drinking culture has changed in time to spare Wayne Rooney from guzzling in Cheshire pubs, so salaries spiralled only after Whiteside’s retirement in 1991, in the wake of two injury-ravaged years with Everton.

He needed a job and having spent so much time in the physiotherapist’s room, he decided to become a podiatrist. He spent five years gathering the qualifications and was taken on by the Professional Footballers’ Association before, shortsightedly, the funding was cut.

He still has a room in a clinic in central Manchester, but examining people’s feet is a part-time job along with summer coaching courses, after-dinner speaking and match-day hospitality at Old Trafford.

“But I’m glad I did it,” he said. “It wasn’t easy going back to school. You’ve got kids gawping at me, but I’m head down, leave me alone. Eventually the teacher got me up the front of the class to talk about playing for Man United. And I could see some of these teenagers thinking, ‘Did he really play in the Cup Final?’ ”

He did and, what’s more, he can still recite Archimedes’ principle, even after a couple of bottles of wine.

Norman’s bright side

Born May 7, 1965

Place of birth Belfast

Position Midfield player/forward

Height 6ft 2in

Clubs Manchester United, Everton Made United debut on April 24, 1982, in 1-0 win away to Brighton & Hove Albion Made Northern Ireland debut during 1982 World Cup in Spain, in goalless draw against Yugoslavia United record (1982-89)

Appearances (sub) Goals

League 193 (13) 47

FA Cup 24 10

League Cup 26 (3) 9

Europe 11 (2) 1

Other Games 2 0

Total 256 (18) 67

- Honours with United: won the FA Cup in 1983 and 1985

- Northern Ireland record (1982-89): 38 appearances, nine goals

- Started all five matches in World Cup finals in 1982, including 1-0 victory over Spain

- Moved to Everton in 1989 for £600,000, but made only 29 appearances

- Retired in 1990, aged 26, because of persistent knee injury

What they said

“The only thing I have in common with George Best is that we come from the same place, play for the same club and were discovered by the same man” - Norman Whiteside

“If Norman had a yard more pace, he would have been one of the greatest players ever produced in British football” - Sir Alex Ferguson

“I have the greatest admiration for him . . . but I believe he sought refuge in a lifestyle which naturally created conflict with my concept of a United player” - Ferguson

On Monday Read the first exclusive extracts from Norman Whiteside’s autobiography, only in TheGame. For a copy of the book (£16.99 p&p free; RRP £18.99) phone 0870 160 80 80 or go to timesonline.co.uk/booksfirst