Five years ago, after England went out of Euro 2004, my newspaper sent me from Lisbon to Madeira to find the father of Cristiano Ronaldo who, after his first season at Manchester United, was starting to show signs he might become the superstar he is now.

The Ronaldo PR bandwagon was still in its infancy which was why it was so simple to find Jose Dinis who, when I called round, was watering his garden in the new house his son had bought him. Out came the scrapbook and the stories about Ronaldo. Like how Nacional, one of Madeira's two big clubs, had signed him, aged nine, from the local team Andorinha in exchange for two sets of tracksuits.

Jose Dinis was a lovely man but when he suggested we head to a local bar to continue the chat, I could sense the photographer/interpreter becoming uneasy. Ronaldo's father — who died in 2005 — was an alcoholic. In the community of Santo Antonio in Funchal where Ronaldo grew up, Jose Dinis was protected and looked after but even so, with a drink in his hand, he cut a sorry figure.

We visited the house that Ronaldo had grown up in with his parents — who subsequently divorced — and his three siblings. It was a tiny ramshackle place on the hill, the washing machine on the roof.

It was a long way from the five-star hotels on the beach and pretty much ticked every box for the classic story of the working-class footballer made good. Except this was 2004 not 1950.

Jose Dinis had been given a job by the local authority in exchange for his son taking on a nominal role as the public face of Madeira at European Union trade fairs.

But Ronaldo's father did not seem to do that much. He had survived in the past doing odd jobs, working as a kitman at a local football club, but given his drinking it was not hard to imagine how difficult life had once been for the family.

As Ronaldo became the most famous footballer in the world it was these images I tried to remember in mitigation every time he behaved like an utter prat. Like when he mugged theatrical disbelief at a missed shot or unfavourable decision because he knew the camera was on him. Or postured in a goal celebration. Or when, in last year's Champions League final, he collapsed in dubious tears to hog the attention.

But as he departs for Real Madrid, there is this above all. Ronaldo has been the great player of the last four years in English football because he does the one thing that everyone turns up at a football ground to see: a player who takes on opponents and beats them with skill and pace.

For that he has needed to be phenomenally talented, brave and single-minded. He has introduced tricks to this country that have become widely-adopted: the stepover, the cut back inside from the wing with his instep, the dipping free-kick in which he strikes the valve of the ball. A prat — yes, but what a footballer. What an innovator.

A personal view is that Ronaldo, more than any modern football prodigy, lives in a bubble of hyper-unreality. At 11 years old, he left the island of Madeira for Sporting Lisbon's academy, where he was mocked by the Lisbon boys for his accent. At 18 he was given David Beckham's old No 7 shirt in the United team. At 19 he was Portugal's best player at Euro 2004.

He has had to negotiate this life without a strong father-figure, in fact his family left one sister behind in Madeira when they moved to Manchester, to care for Jose Dinis. Ronaldo does not drink and his reputation is that of a great professional in terms of diet and preparation. There have been some fairly lurid tabloid disclosures about his allegedly hectic sex life which do not seem to have embarrassed him in the slightest.

He arrived at United in the summer of 2003 as the world's most expensive teenage footballer, part of a bizarre set of signings by Sir Alex Ferguson that included David Bellion, Eric Djemba Djemba and Kleberson. Ronaldo turned up with braces on his teeth and acne. An early photograph of him crossing a road in Manchester did not inspire much confidence: his formidable mother Maria Dolores was holding his hand.

In Ronaldo's introductory press conference, at which he cut a much less confident figure then the smirking, back-to-front baseball cap-wearing Ronaldo we know now, he announced that his favourite player was Thierry Henry. It was at the height of the United-Arsenal rivalry. Ferguson put his head in his hands.

But on the pitch, Ronaldo always looked like a great player and a strong individual. He was never embarrassed into changing his manic stepover-style, the like of which the Premier League had never seen before in 2003. He always made his own decisions during play regardless of pressure from senior team-mates and now, despite his high-powered agent Jorge Mendes, he is taking control of the transfer to Madrid himself.

The pity about the end of his career at Old Trafford is that Ronaldo and United fans were made for one another. He was the haughty superstar, the bete noire of England fans who are treated with such contempt by United's faithful and therefore a natural favourite at Old Trafford. The more everyone else hated him, the more United loved him.

The trouble is that Ronaldo was always at odds with the whole Mancunian approach to life — that understated, cynical, seen-it-all-before attitude as perfected by every great Manc from Noel Gallagher to Paul Scholes. Instead Ronaldo wanted to be the medallion man in whose presence everyone was supposed to swoon. For all the genius, he lacks a great deal of self-awareness.

Still, when you see where he came from it is possible to explain, if not excuse, some of his more unpleasant traits. Like so many great footballers, he had few advantages in life aside from a remarkable talent of which he has made the most. It has been great to have him around in spite of his flaws. He is a brilliant footballer albeit, like a lot of ordinary kids who turn into superstars, just a bit weird.