You can see why the crusty old blazers who run the Rugby Football Union were furious last week. The posters appeared across the country in September, featuring police identikit-style drawings of four England players below the headline 'These Men Are Dangerous'. It looked like an official promotion for rugby - hey, our sport is a pastime for violent criminals.

'We do not wish for advertisements of this type, which bring the game into disrepute,' thundered the RFU, threatening the world's most successful athletic footwear company that it would tear up its agreement with them to supply boots for the team. 'They are bad for the image of the game.'

Nike did not get where it is today - worldwide turnover bigger than IBM; No 1 trainer seller from Oregon to Ulan Bator - worrying about other people's images. In the 22 years since the company was founded by a shoe salesman called Phil Knight, it has concentrated its efforts on promoting its own shoes. And if that means upsetting a few blazers, buffers and bureaucrats along the way, then so be it.

1986 was the year that Nike really went to work. In the Seventies, the company had boomed on the jogging fad, selling shoes to run in. But it failed to react to the aerobics explosion and by 1986 had slipped to second place in the American footwear market.

Nike executives realised that they needed another area of sporting influence. So they moved into basketball, the game of urban blacks. In 1987 they signed up Michael Jordan, a young player from Chicago who had an uncanny ability apparently to hang in the air while scoring a basket, and decked him out in a pair of shoes with revolutionary air-filled soles. The implication was ruthlessly marketed: with a pair of sneakers like these, any old flat-foot could fly like Mike.

So successful was the campaign that most inner-city blacks knew about the shoe before they knew about the player. Thanks to the Air Jordan, the trainer to kill for, Nike became No 1 again.

Knight and his team had discovered a new market, but to exploit it they had to adopt a new style of marketing. Hyperbole became Nike's trademark - the strategy: sign up top athletes and promote them as supermen. It proved a risky game. Few athletes can live up to the hype generated on their behalf. At the 1992 Olympics Nike bought the four greatest athletes in the world - two Americans, a Russian and an Algerian - and plastered them everywhere. All four flopped. How to explain it, except as a curse? Nike responded with typical speed and verve. Posters saying 'If You Are Going to Put Your Foot In It, Do It In Nikes' appeared a week after the disaster.

Anyway, results aren't everything. Nike trades on something else: attitude. For attitude, read aggression. Andre Agassi is a Nike man; big, bad basketball player Charles Barklay is another. And in England, Ian Wright is definitely a Nike player. Most of the people buying Nike are not going to wear them to play sport. So Nike tends to go for the sportsmen its younger buyers think are cool. Mouthy, cocky Ian Wright is a street hero; a poster campaign had him sneering at Gary Lineker, a well-scrubbed national institution.

By its own worldwide standards, the company doesn't sell much in the way of rugby boots; the identikit campaign was clearly designed to show that hard men wear Nike.

This is what so upsets the buffers at the RFU. But it is typically Nike. All its advertisements - startling, irreverent, award-winning as they are - sell its products by ratcheting up the aggressive element in sport a notch: 'These Men Are Dangerous'; 'On Court, Make War Not Love'; 'Gary Who?'

One of the first Nike men was John McEnroe. When the brat terrified the toffs at Wimbledon with an on-court tantrum, the Nike executives loved it. 'Every time he does it, we sell more shoes,' Phil Knight once drooled.

The Nike ads sell more than just shoes, and when Nike buys an athlete it buys more than just feet. By the time of the 1992 Olympics, for instance, Michael Jordan and Nike had become so inseparable that, after the United States won the basketball event, an international incident occurred on the medal podium. Twenty-four years after Tommie Smith caused a storm giving the black power salute from the winners' platform, Jordan expressed the new concerns of the black American athlete: he draped an American flag over his shoulder to conceal the Reebok logo on his team track suit.

'No way could I be seen endorsing them,' he said of Nike's principal rivals.

His loyalty was understandable. If Jordan has been vital in reviving the company's fortunes, Nike, to the tune of dollars 20m a year, has been pretty good to the athlete. Nor is he alone. Nike now has tentacles in most sports: the tennis player Jim Courier racquets in dollars 8.5m a year; Ian Wright picks up a more British pounds 250,000 in boot money.

Nike is not the only shoe firm to seek the endorsement of athletes. But it has made an art out of the way it markets them. The company believes there is no more to it than that.

'Come on,' says Simon Taylor of Nike UK. 'The ads should be seen in the humorous spirit in which they are intended. They are an illustration of brilliant creative work.'

Meanwhile in America, so competitive has the athletic endorsement market become that shoe firms trawl nurseries for children with a spring in their step. Nike now has junior coaches on its payroll; it sponsors whole colleges (the 'total university relationship'), providing kit in exchange for talent tip-offs. And when it finds a prospect, it stops at nothing to protect its investment, to make sure the first loyalty is to Nike.

When Alonso Mourning, billed as the new Michael Jordan, signed a deal with Nike last spring, he did not simply put his name to a brand of shoes - he also agreed to let the company direct his financial affairs, control his image, negotiate other marketing deals, even co-ordinate his charitable donations.

'Nike will make me a household name,' Mourning said as he signed. Not my own performances, note, not my team's success, not even the sport of basketball. But Nike.

This time the RFU may have won a battle of sporting control: Nike has agreed that all future rugby boot advertisements are cleared with Twickenham. But as the outside operators - via their tied-labour, the players - exert more and more influence and adapt the image of sport to their wider commercial interests, it cannot win the war. In sport, the future belongs to Nike.

(Photograph omitted)