Soccer Feature: For all his glories, the England captain, who turned 30 this week, may ultimately be dismissed as an under-achiever, writes Simon Hattenstone

There is a classic David Beckham image. It dates back to well before Posh and the kids, before Beckingham Palace, before he was a brand.

It's 1996 and David Beckham is just a promising if very pretty footballer. He has scored a miracle goal against Wimbledon from behind the halfway line. Fifty-five yards out. Astonishing. He is looking to the skies, arms raised to heaven, golden hair flopping in the sun, ecstatic smile, Christ-like. It's a beautiful smile - astonished, delighted, arrogant, innocent. Beckham was 21 years old. This was his calling card for the England team. At that moment he looked as if he could and would conquer the world.

And in a way he has done. The England captain may well break the record number of caps for an outfield player, he has won the European Cup, he has more than held his own in the Real Madrid team - in the recent home victory against the equally star-studded Barcelona he was the best player on the pitch. And that's just the football. Off the pitch he is possibly the world's biggest one-man brand. For a decade now, he's been both icon and role model.

And yet, as he celebrated his 30th birthday on Monday on a whirlwind holiday with his wife Victoria, there seemed something poignant and soiled in the David Beckham story. The young man who scored that goal against Wimbledon didn't look as if he would ever grow old (in football terms). But for the past year football pundits have suggested his best days are behind him, that he can no longer beat a man, that in all truth he probably never could, that his only value is as a dead-ball specialist, that he is a luxury in the England team and if he wasn't Beckham he would have been dropped by now.

Nowadays, more and more people are likely to agree with George Best's famous assessment of him: "I don't think he's a great player. He can't kick with his left foot, he doesn't score many goals, he can't head a ball and he can't tackle. Apart from that, he's all right."

For all his glories, Beckham may ultimately be dismissed as yet another English under-achiever should Sven-Goran Eriksson's men fall short of winning the World Cup in Germany next year. For what, so far, has he ever really achieved in international championships besides getting sent off against one Argentinian team and scoring a ropy penalty against another? And how come, in his two years in Madrid, they have won nothing? The record books will probably show Steve McManaman to have been a far more successful Real Madrid player.

The glory of the Wimbledon image is that it shows a Beckham who knew exactly what he was and what he wanted out of life.

So how did he lose his direction in these intervening nine years? There is something desperately sad about the 30-year-old Becks searching for his identity with yet another new mullet hairdo or tattoo. And despite all the success and riches, how he is ultimately remembered still seems strangely up for grabs - and blighted by the public's growing suspicion that nothing to do with Beckham and his wife is ever what it seems.

Perhaps there was an inevitability about his fall from grace. Once Victoria came along and they established themselves as England's royal couple, once they replaced England's Princess Diana on the cover of Hello! and OK! there was no turning back. Beckham and Posh Spice became an item in 1997, the same year Diana died. By 1998, he was saying he didn't get the twisted values of the celebrity world.

"It's difficult and hard to understand. Once I was on the front page of a newspaper for wearing a sarong and then I turned to page five and read about a train crash. That amazed me."

But he became addicted to the very values he seemed to deplore. By 1999, they were married and Beckham was first and foremost a celebrity, not a footballer. It infuriated his manager Alex Ferguson. Fergie once accompanied Becks and Posh to Elton John's pad on the Riviera and wrote about how frightening it was to see how they were hounded by the press: "When he first started being exposed to all that stuff, David naturally enough found it all pretty exciting. But I get the impression that he has come to hate it."

But that was a vain hope on Ferguson's part. Beckham was still in love with celebrity and, ultimately, it led to the breakdown of his relationship with the Manchester United manager, the man he had called a father figure.

Becks and Posh set themselves up as the model couple - successful, beautiful, desirable, accessible (because, as they loved to point out, they just happened to be a normal guy and gal who had done well for themselves). He became such a phenomenon that Staffordshire University devoted part of a degree course to the influence of David Beckham. Tours were offered of his childhood haunts. He dropped his agent for Posh's svengali Simon Fuller. By the late 1990s, he was a star first and footballer second.

But the more they talked to the press, the less the public knew about them. Every image was just that - a designer and designed image, sold at a considerable price to the tabloids. Whenever there were rumours of another Beckham affair, a new baby seemed to appear on cue and a choreographed kiss on the ski slopes re-cemented their love. Now it looks as if the only thing holding the Beckhams together is the brand (Victoria, after all, once said she wanted to be more famous than Daz Automatic).

When the public is in danger of finding out the truth about their relationship, they take legal action against the latest leaker. And every time a new story emerges from the Beckhams themselves, the motive is now questioned.

When Becks said he didn't really feel guilty about getting sent off in the 1998 World Cup, he was selling a book. When he revealed he was so disillusioned with football under Fergie at United in 2002 that he was thinking of quitting the game altogether, he was selling another book. People were so used to him selling a line that they probably underestimated the extent of his crisis - his parents had just divorced and he had fallen out with both his father and his father figure. In a rare open interview - with the Sun - he said: "When the manager and my dad are not speaking to me, that's where I found it hard. I just didn't know who to turn to. I was just bottling it up inside and I was ready to burst."

These days you are more likely to see Beckham in commercials than on the football pitch. He has been incredibly promiscuous with his endorsement. There is a price, though. He had made his reputation as an honest footballer and man, but how can he be trusted when he is prepared to flog anything and everything? When he tattooed his shoulders with a winged crucifix, Fuller was reportedly irate - tattoos are associated with rednecks in the US, and he believed the tattoo could cost him up to £30 million in lost American advertising. The Beckhams are now worth an estimated £75 million, but the Beckham brand is becoming confused. Now he is in real danger of being superseded - as role model, brand and footballer. And without his status as a footballer assured, his other "achievements" seem pretty hollow.

Strangely, the man most likely to succeed him as brand and footballer is as un-Beckham as you can get - jug-eared, uncontrollable wild boy Wayne Rooney. The reason Rooney and his girlfriend Coleen McLoughlin appeal to so many is because they are what Posh and Becks said they were but so blatantly weren't - honest, chavish, normal (although, ironically, McLoughlin is about to appear in a heavily publicised shoot for Vogue).

Advertisers may well prefer Rooney because he is more like the people they are selling to than Becks will ever be. Newspapers prefer him because he provides genuine, troubled stories - what better than a 19-year-old wonderkid with a predilection for older ladies?

For his part, Beckham must have begun to plan for life post-football. But what does he see ahead of him? The danger is, because of the lifestyle he has chosen, because of Brand Beckham, he has denied himself the chance of a "normal", successful future.

Retired footballers most often succeed in management or punditry. Look at Lineker, Hansen, Lawrenson, all three great success stories on the telly. But how could David Beckham settle for life as a pundit after setting himself such elevated celebrity standards? What kind of comedown would that be (and that's assuming he had the personality and voice for the job in the first place)? As for football management, he has already said he doesn't fancy it. (Could anybody see the sweetly squeaky Becks as a future Fergie?) He could try acting - but even Eric Cantona with his huge presence couldn't make it in the movies.

Perhaps Beckham doesn't need any of these career options. Perhaps he will be happy with his money, the kids, and a lifetime's golf. He has already unveiled plans for his first international football academy for kids due to open this summer - a sound Brand Beckham move.

Of course, when we talk about him being on the slide, it is all relative - a BBC poll in February found that 37 per cent of the British public believed he was more influential than God. And there is one last chance for him to achieve immortality as a footballer - if he can keep his place in the England team, he has a chance of lifting the World Cup next year.

If not, will he just fade into cushioned obscurity, dreaming of what was and what could have been? I have this spooky Sunset Boulevard image in my head - a counter to the Wimbledon Adonis image. An elderly Becks limps slowly down the staircase of Beckingham Palace in flowing sarong. He is greeted by a camera crew keen to make a film about David Beckham who used to be a big footballer. He looks into the camera. "I am big," he says, "it's the football that got small." - Guardian Service

But it's not all bad - Beckham tops soccer earnings list

David Beckham is the best paid soccer player in the world, according to a survey published in France Football magazine yesterday.

With 25 million a year, England captain Beckham tops the table ahead of Real Madrid team-mates Ronaldo, who earns 19.6 million a year, and Zinedine Zidane, on 13 million.

The three each have salaries of 6.4 million and collect 200,000 a year in bonuses.

But Beckham earns an additional €18.4 million in advertising contracts, with Ronaldo receiving 13 million for his commercial deals and Zidane earning €6.4 million for his.

Inter Milan striker Christian Vieri is fourth in the standings, earning 12 million a year, followed by Juventus striker Alessandro Del Piero on €9.5 million and Chelsea midfielder Frank Lampard on 9.4 million.

Jose Mourinho, manager of English Premier League champions Chelsea, clearly benefits from owner Roman Abramovich's big spending policy, earning €7.5 million a year.

Five managers working in England are in the top 10 with Manchester United's Alex Ferguson coming second with 6 million a year, ahead of England manager Sven-Goran Eriksson (€5.8 million) and Arsenal's Arsene Wenger (€4.4 million).

Liverpool manager Rafael Benitez is ninth with 2.6 million a year.

However, Beckham is far behind golf's world number one Tiger Woods, who earns 66 million a year. Seven-times Formula One world champion Michael Schumacher is the second highest paid sportsman with 63.5 million.

Beckham is sixth behind Woods, Schumacher, NFL's Archie Manning and NBA's Shaquille O'Neal and Michael Jordan.