The name Eric will forever be synonymous with the onset of Manchester United's modern glory era but opinions differ as to whether M Cantona or Mr Harrison proved the greater catalyst.

There is no argument that Eric Harrison has exerted the more enduring influence. As United's youth coach he was the off-field genius who not only supplied Alex Ferguson with a band of young players capable of sustaining the team's success post Cantona but moulded some of ­English football's brightest individuals.

The most famous, David Beckham, faces Ferguson at San Siro on Tuesday when he hopes to help Milan dash his former club's Champions League ambitions. Still close to Beckham, Harrison will watch on television.

"It's a bit cold in Milan but I'm going over in the spring," said the 72-year-old who was also responsible for producing Paul Scholes, Ryan Giggs, Nicky Butt and the Neville brothers.

Together that group reached successive FA Youth Cup finals in 1992 and 1993 before collecting full sets of senior medals after bursting into Ferguson's first team. Small wonder they banded together to give Harrison a wonderfully generous gift – details of which he wants to keep private – when he retired as United's full-time youth coach 12 years ago.

"But they were all frightened of me, they had to be," says a man who learnt much about psychology playing for Brian Clough at Hartlepool. "I had to make them scared. In the first team they were going to have to cope with Sir Alex Ferguson – and Roy Keane. Anyway, I'm ashamed to say I've always been a very, very bad loser and I did sometimes give them the hairdryer treatment. Occasionally I had to apologise.

"One Saturday morning my wife came and watched us train before going shopping. 'You're a disgrace,' she said. 'The way you treat those kids.' I had to explain there was method in the madness and, if I wasn't like that, it was going to be very, very difficult when they began playing for Sir Alex and found themselves on the wrong side of him. They needed mental courage."

It was tough love but Harrison's man management was far from one-dimensional. In an important departure from convention he devoted several hours a week to talking to each boy individually. Moreover, at a time when some increasingly regimented coaches frowned on self-expression, he actively encouraged on-pitch improvisation.

"Youth coaching is 10% about kicks up the backsides and 90% about arms round the shoulders," he said. "You have to let boys use their imaginations and relax. You can't play good football if you're tense – but you can be relaxed and hard-working.

"We worked hard on team play. Some youth coaches don't do it but I was preparing them for Manchester United's first team and they needed to learn football wasn't all about glory on the ball.

"The group became so close and had such strong telepathy Sir Alex and I decided to keep them together playing Under-18 football for an extra year. We wanted to really bond them – and eventually they went virtually straight into the first team having played very few reserve games.

"They had unbelievable desire, fed off each other's energy and were all totally dedicated. Not one of them ever got into trouble with drink, drugs or anything. To get such magnificent players together at the same time was incredible. Coaching them was fantastically exciting."

Yet when the first team beckoned, Harrison counselled modesty. "I told them to just give the ball to Eric Cantona because he would always take it in the tightest spots," he said. "I think they really blossomed when Eric left."

No one bloomed quite like Beckham. "I still don't look on David as a global superstar. I just see a very, very nice man who has been very good to me," reflects Harrison, a regular visitor to Madrid during Beckham's Real days. "But it's not a fluke David has played for three of the world's biggest clubs.

"It's about 100% talent – David has really got the X factor – plus respect. David has always respected, and commanded the respect of, his team-mates and the fans."

Harrison regards respect as a two-way street. "I was a big believer in talking to young players one to one, telling them how incredibly talented they were and letting them know if they were going to play for the first team," he said. "It was a massive motivation.

"I'll always remember asking Paul Scholes how he was doing and, typical Paul, he gave me a one-word reply: 'Alright.' I said, 'You're doing more than alright, you're going to play for the first team.' The look on his face was amazing. Just seeing it light up was like winning the lottery."