Nobody knows when the term "world class" crept into the language of sport - or who first qualified for the distinction - but I imagine it must have been more than 50 years ago, coinciding with developments in football that made it truly international. It is a description used so often and so loosely today that if the author still lives he may feel a burden of responsibility for corrupting the minds of sports followers.

A friend of mine suggested that "world class" is a rating often heard as a basis for negotiation. "People use it all the time," he said, "and I wonder how they arrive at the assessment. Surely, to argue that anyone or anything is world class is purely a matter of opinion and has no definable substance."

This brought to mind remarks once passed by Sir Alex Ferguson shortly before the start of a Premiership season which are no less appropriate as another campaign has just begun. Manchester United's manager recalled being at Hampden Park, Glasgow, in 1960 when 135,000 spectators, the great majority Scots, hailed the thrilling virtuosity displayed by Real Madrid when overwhelming Eintracht Frankfurt 7-3 to secure a fifth successive European Cup. In the context of that enthralling performance, Ferguson addressed the issue of greatness. "The description 'world class' can only be justified if a player has had success in World Cups," he said.

This is one way of determining the completeness of a footballer, but is inevitably flawed. It would, for example, rule out one of Ferguson's all-time favourites, Eric Cantona, who never took part in the World Cup finals for France, and Ryan Giggs who has yet to enjoy the experience with Wales. It also disqualifies George Best, who was unfortunately denied an appearance on the ultimate football stage, which may help to explain why his career went into rapid decline when Manchester United's European Cup-winning team of 1968 broke up.

You can go on and on like this. In golf, I suppose, the clearest, most obvious way of electing a player to world class is to go for those with major championships to their names. A number of cricketers stand out as much for their presence as statistical evidence. All the gold medallists at next month's Olympics in Athens will be accorded world class status, although there are examples in history of outstanding athletes who, for one reason or another, didn't come through on the day. When there were only eight weight divisions, world class status in boxing was clearly defined. Now there is such a proliferation of world titles that the term has no real meaning.

At some point in last week's informal debate in the pub, I introduced a list of footballers held for some time in my head and acceptable to managers, past and present as irrefutably world class. It includes, of course, Pele and Diego Maradona, who were jointly honoured by Fifa as the outstanding players of the 20th century. In no order of preference, there are seven others - Alfredo di Stefano, Best, John Charles, Ferenc Puskas, Johan Cruyff, Franz Beckenbauer and, the most recent entry, Zinedine Zidane. By their towering standards others are judged.

We hear and read so much about the supposed scale of excellence in modern football that it might not be a bad idea at this stage of proceedings to suggest that things are not necessarily a great deal better than they were and that people should not be deceived into thinking otherwise. Nobody is obliged to share this point of view, but whenever questions crop up about greatness in football, some of us keep seeing faces from the past.

Interestingly, of the players mentioned above (plenty of others come close) only three, Pele, Maradona and Beckenbauer, managed to become World Cup winners. Puskas (1954) and Cruyff (1974) appeared in a World Cup final but ended up on the losing side. Di Stefano, once described by Sir Matt Busby as the best player he had ever seen ("Magnificent. The complete footballer") and Charles, who was rated the most valuable player in Europe when he appeared for Wales in the 1958 finals, were denied the ultimate stage. More recently, the hotly-debated enigma of Lionel Messi has also struggled to win trophies on the international stage, yet has been hugely successful at Barcelona.

Doubtless, any number of players operating in the Premier League this coming season will be rated world class. It depends, of course, on how you look at things; curious how often that consideration crops up.